The above cartoon was produced by an anonymous cartoonist.

Day-to-day log of the 2008 search season:

10-18-07 to 3-29-08, 4-13-08 to 4-21-08, 6-14-08 to 6-28-08

10-1-07. I'll have something new in my bag of tricks when I head south again next week. I'm as excited about bino-cam as I was about paddle-cam last year. My friends at work, Greg and Mike, modified the mount, which is marketed as Bino-Brac by Astronomy-Shoppe, so that the camera sits lower on the binos and is more securely mounted. I will line up the camera so that it sees the same field that is seen through the binos at maximum magnification. It's a shame that I didn't come up with this idea a long time ago. When I got the video in the Pearl in February 2006, I kept the camera running in my right hand while trying to spot the bird through the binos using my left hand. I alternated between looking through the camera and the binos. Since the image is very small in the viewfinder, it was impossible to see the bird through the camera. When I was looking through the binos, the bird must have been hiding behind the branch on which it was perched. So I never saw the bird other than detecting motion. By aiming the camera and binos simultaneously with bino-cam, I probably would have gotten an incredible look at a perched ivorybill and much better footage. When I got the video in the Choctawhatchee in January 2007, I set paddle-cam on my lap, aimed it in the direction of the birds, and kept watch with binos. I got a good look at the dorsal side of a right wing when one of the birds flew to a different perch. I would have gotten good footage if I had been using bino-cam. I plan to continue using paddle-cam while in the kayak this search season. The intended application of bino-cam is tree-top observing. I will use the high-def camera with a 2X extender lens and the focus set to infinity. With this set-up, I won't have to decide between reaching for the binos and reaching for the camera, and I should be able to get good footage out to at least a few hundred meters if the light is good.

10-5-07. My car is having problems, and they have to order one of the parts. So my return to the Pearl will be delayed for a week or so.

10-15-07. The part for the car arrived, but the repair shop botched the job. Before heading south, I'm going to have to get this resolved and then drive the car locally for a few days in order to make sure it's ready for the trip. I did some additional testing with bino-cam. I put the camera on full zoom in order to check the alignment of the camera with the binoculars. The results were very promising, as illustrated by these images of perched Mourning Doves and a flying Blue Jay (the images are slightly blurry since the focus set at 50 m and the birds were more distant). The images were reduced in size from the original high-def video frames.

10-16-07. The car is finally ready for the road. I'm planning to get underway tomorrow morning.

10-18-07. My car, which one of the visitors to the Pearl aptly named the Ivory-bill Bomb, just died near Mobile, Alabama. I was fortunate to be approaching an exit (it was actually Exit 13) when ominous metallic noises started coming from under the hood. Considering all the long trips that I've taken in old cars, it's amazing that something like this hasn't happened to me before. The repair shop agrees with my assessment that the engine is blown. In accordance with several of Murphy's Laws, this had to happen after I waited around to have repairs done, installed new tires, and got nearly a thousand miles into the trip. I'm going to try to get a deal done on a new car in the morning.

10-19-07. I'm at the dealer picking up an '08 Honda Civic. It's a nice little car, but I hate to let go of my trusty old '78 Fairmont.

10-20-07. I have arrived back at the Pearl. Besides getting settled in, I need to find a roof rack for carrying the kayak on the Honda. The weather is gorgeous, and the birds are very active. The Great Horned Owls, Bubba and Virginia, were calling this morning near the house in Waveland.

10-21-07. I wasn't able to locate a roof rack this weekend. I'll check the on-line options on Monday. I don't want to load the kayak on a brand-new car without a proper roof rack. I'm definitely missing the Ivory-bill Bomb, which would go just about anywhere with a kayak or canoe on the roof.

10-22-07. It's been raining all day. I have located a roof rack but won't be able to pick it up until tomorrow.

10-23-07. I have obtained a roof rack, but another obstacle has arisen. I seem to be getting sick and have an appointment with the doctor tomorrow morning. I hate to miss another day, especially since the weather is finally clearing up, but it's essential to watch your health when doing field work.

10-26-07. I finally made it out in the Pearl today. It was great to be back in the kayak. The weather was very nice, and there was lots of woodpecker activity. I saw an immature Red-headed Woodpecker in the interior of the Pearl. I usually only see this species on the edges of the Pearl and don't recall any previous sightings in the interior. Since Katrina hit more than two years ago, a huge branch had been hanging precariously from the top of a tree. I always wondered how it stayed up there. I noticed this morning that it finally fell sometime since I was last out there in July.

10-27-07. I decided to stay in today since I still have a sore throat that seems to be similar to the one that put me in the ER in April 2006. While back home in Virginia, I had a lot of catching up to do and little time for exercise. I got out of shape and don't have much stamina. The thought of paddling for several hours and then climbing a cypress seems very daunting right now. I'm going to have to gradually work myself back into field condition. If I were on a professional ivorybill searching team, I would probably be put on waivers for showing up at camp out of shape.

10-28-07. I visited an area further north in the Pearl. There's a ridge up there that I was hoping would have trees providing good views out over the swamp. There are some pines on the ridge that look promising. Pines are pitchy and brittle according to the experts, but I might give one of them a try.

10-29-07. Due to a busy day in the office, I didn't make it out in the field today. After the hike yesterday and the kayak ride on Friday, I feel like I'm starting to get back into shape. The thought of a trek deep into the Pearl seemed intimidating a few days ago, but I should be ready for one this week.

10-30-07. On the way out of Stennis last night, I was sad to see a Southern Fox Squirrel dead on the road. It was at the spot where I used to see one several months ago and may have been the same one. This specimen was 25 inches from the tip of the nose to the tip of the tail. I spent three hours in the kayak this morning. There was a great deal of woodpecker activity. Familiar landmarks from Katrina are gradually disappearing. An M-shaped branch that appears on the bank in the through-the-gap video has broken off. I found a spruce pine in a good location that has what appear to be strong branches more than 80 feet up. This tree should provide a great view over the 2006 hot zone, but I'll have to consult with the experts since pines aren't as safe as cypresses.

10-31-07. It's going to be another busy day in the office, but I'll try to get out for a while late this afternoon. I just started reading "Discovery: Great Moments in the Lives of Outstanding Naturalists," a wonderful book by John K. Terres that includes an account of Don Eckleberry's visit to the Singer Tract.

11-1-07. I took the climbing gear out to the pines and sized them up (there are actually two of them right next to each other). There are good-sized branches fairly high up, but it's not clear if they're high enough to see over the surrounding forest. I took more height data and photos, which I'll evaluate tomorrow. I'll also post some photos tomorrow, but I'm too exhausted right now. After checking out the pines, I kayaked up beyond the area where I broke my arm and saw two huge gators. I looked for tall trees hoping that we had overlooked one in June. There's a cypress that looks promising, but I'll have to evaluate the data tomorrow.

11-2-07. After checking out the pines yesterday, I visited a cypress that we rigged in June. I've never climbed that tree, which is miles to the north of the other trees that we rigged. On the day it was rigged, I didn't have a clinometer for measuring heights (a laser rangefinder is also required). I measured it yesterday and was surprised to find that it's rigged at over 80 feet. The view is partially blocked by tall hardwoods in one direction, but it provides a good view in other directions. Since this tree is much easier to reach than the others, I'll give it a try in the near future. I didn't climb it yesterday since it was getting late when I arrived.

11-3-07. Yesterday was another busy day in the office. I didn't make it out in the field, but I did stop to marvel at Comet Holmes on the way out of Stennis late last night. It's easy to see and quite an unusual comet.

11-4-07. After another long day in the office yesterday, I arrived back in Waveland about midnight and found the door wide open and gang graffiti painted on the front of the house. They smashed the front door window with a brick and rummaged through everything inside. I don't leave valuables in that house, but I was concerned about my copy of John K. Terres' book that I was in the middle of reading. There apparently aren't any scholarly types in that gang. The piles of books were knocked over, but none of them were taken.

11-5-07. Order has been restored. I repaired the damage to the house and painted over the graffiti. I also started cutting the weeds back in the yard. The birds like a weedy yard, but it's not good for an isolated house to appear vacant.

11-6-07. Early this morning, I passed by the tallows and found them loaded with fruit, which probably isn't ripe yet. I spent the morning in Tree 6. It was my first time in that tree, which is the only one that we have rigged in the hardwood zone. I got up to about 78 feet, but the view isn't as good as it is in Tree 5 since the trees are taller in the hardwood zone. The view is pretty good in this direction but not as good this direction. A Wood Duck came from this direction and flew by within twenty feet. I could hear the wind whistling through its feathers.

11-7-07. I've had pain in the heal/arch area of my right foot for more than a month. It really flared up yesterday, probably as a result of lugging climbing gear. I'm going to let it rest for a day or two and will try to see a doctor to have it checked out.

11-8-07. I decided to let my foot rest for another day. I inserted pads into my shoes a few days ago, and that seems to be helping. I have an appointment to see a podiatrist next week. In the meantime, I will spend some time in the kayak.

11-9-07. I took care of some work at the house in Waveland and didn't make it out in the field.

11-10-07. I spent the morning finishing up some work at the house.

11-11-07. I took a kayak ride through the area where I recently saw two huge gators. On the way up the channel, I inadvertently paddled right over one of them, which thrashed violently and gave the kayak a hard blow with its tail. The loud sound of the impact gave me the impression that gators must be very bony just beneath the hide. At about the same spot on the way back, a gator thrashed a few feet away and gave me a good splash. Those encounters really got the adrenalin flowing.

11-12-07. Due to an upcoming conference, I'll be tied up in the office today and possibly one or two other days this week. Yesterday I noticed that someone cut two fallen trees that were blocking the waterway that goes to Tree 6. This will make it easier to get there by kayak. I have ordered a gear sled that will make it easier to get to Tree 5. The shortest route to that tree involves an hour walk through the swamp. When carrying the climbing gear, the extra weight causes my feet to sink much deeper into the mud, which turns the walk into a death march. I plan to spend more time in the tall trees now that it will be easier to get to them.

11-13-07. I received the gear sled and am very excited about it. It's lightweight, durable, and just the right size for a loaded backpack and climbing gear. The low-profile design should make it stable when going over rough terrain. I'm eager to try it out on the route to Tree 5 but may not have a chance until Friday. I'm going to the doctor to have my foot checked tomorrow, and it's looking like wind and rain on Thursday. The recent gator encounters got me to thinking about the possibility of being attacked. While growing up in Florida, the kids in the neighborhood spent nearly every hot summer day cooling off in the Hillsborough River. We knew there were gators, but we never worried about them since we were told that they don't attack people. As a matter of fact, there have been quite a few fatal attacks over the years. Most of them occurred in the summer months and were by gators greater than eight feet in length. The two gators that I saw a few weeks ago are in that category. I first saw one of them in the spring, and it made me feel nervous about kayaking through that area. Kayaking shouldn't be a problem with cooler weather coming, but I'm a bit concerned about stumbling upon a gator while wading through sloughs. Based on the encounter in the kayak the other day, it seems that a gator could easily break your leg with a tail whip.

11-14-07. I've been thinking about the sightings in the Pearl last year and looking for clues about ivorybill behavior. I found a hot zone, and the birds remained there for at least five days despite the fact that I flushed them several times. The bird in the video remained in the area for more than ten minutes after being flushed. Before flying away, it watched me from a distant vantage point in a tree. That bird was obviously reluctant to leave the area. One of the favorable aspects of that area is that it's relatively difficult to access by land or water. I've never seen anyone in there on foot, and fallen trees keep the boats out. The area is just above the cypress-tupelo zone in hardwood habitat that is surrounded by waterways. A few weeks before discovering the hot zone, I had my first sighting in an area that is similar with the exception that it's not as isolated. I staked out the area for a few days and saw a few small motorboats, and this activity probably caused the birds to move about a kilometer away. These encounters suggest that ivorybills prefer isolated areas and may remain in them for extended periods. There are probably many such areas in the Pearl that I have never visited and will never visit. To make matters worse, ivorybills can easily be missed even when they are nearby. My first sighting in the hot zone was of a bird that flushed from close range on the bank. It was on or near the ground behind vegetation, and I was drifting downstream. If it had not been close to the bank or if I had made any noise, I probably would have missed it. Late that afternoon, I returned to that spot and staked it out. After sitting there quietly for more than an hour, three kents came from point in the woods straight back from the spot where the bird flushed. It probably spent the day in that area, but that was all that I heard. I was fortunate that the birds were for some reason attracted to the riverbanks. If they had been away from the water, it's doubtful that I would have ever found them.

11-15-07. Yesterday afternoon I visited the doctor, who diagnosed the pain in my foot as plantar fasciitis. Gee, I wonder if this could be related to wearing inappropriate footwear? For years, I have preferred cheap sneakers for wet areas since they're lightweight and it doesn't matter if they get covered with mud. After seeing the doctor, I obtained a pair of canvas swamp boots that are lightweight but offer more support. I'm supposed to stay off my feet for a while, but that's not an option right now. I won't make it out today because of high winds, but I plan to go out tomorrow.

11-16-07. Gretchen and I spent some time in Tree 4. It was my first time up that tree, which provides excellent views. The view from above the trees is very different now that most of the tupelo leaves have fallen. This is what it looked like from Tree 2 back in July. A pileated flew by just as I was entering the crown. A Great Blue Heron was perched in a cypress about 300 meters away. A Great Egret was looking for something to eat down below. I tried out the gear sled and swamp boots, which both worked great. It sure helps to have proper gear. My right foot was feeling fine this morning, but now it's throbbing. I might have to take a few days off to let it recover, and that would probably be a good idea independent of my foot with the deer season opening. After finishing the climb, we found that the water had gone down and the boat was partially grounded, but we managed to get it out. On the way back, we checked out some tall trees that have come into view now that the leaves are down. One of them is near where we had sightings last fall and has a huge cavity.

11-17-07. I'm going to stay off my feet as much as possible this weekend in order to rest my foot. It was great to get back up in one of the tall trees yesterday. On the way up, it's always exciting to see trees in the distance gradually coming into view. When you finally get above the surrounding canopy, it's like popping up over the clouds and into the blue sky while flying. One of the highlights of the climb was seeing Tree 5 towering over the canopy a little over 400 meters away. It was my closest view of that spectacular tree from another tree.

11-18-07. Working with Richard Martin and Dalcio Dacol, I've been analyzing the high-pitched calls that I recorded in the Pearl last year. Dalcio heard similar calls in the Congaree and Richard recorded similar calls (along with kent-like calls) while working for Geoff Hill and Dan Mennill as a volunteer in the Choctawhatchee. The high-pitched calls sound similar to the Blue Jay bell call, but the sonogram is quite different from published sonograms of bell calls. We have made comparisons with sonograms of kent calls and found interesting similarities. After twice hearing these calls coming from the direction of an ivorybill (in one case, the movements of the source of the calls tracked the movements of an ivorybill), I suspected that it was a vocalization of the ivorybill. More than a week after recording the calls, I saw a Blue Jay in the same area making calls that matched the sonogram of the high-pitched calls, but Blue Jays are capable of matching sonograms and are known to imitate ivorybills. According to John William Hardy, who analyzed the recordings that John Dennis obtained in Texas, comparisons of Blue Jay and hawk calls "suggest that it is possible for the jay to produce a call so much like that of the woodpecker as to be uncertainly distinguishable using any known device for analysis."

11-19-07. I'm getting ready for a conference next week and didn't have time to get out of the office. I saw something interesting here at Stennis while walking to lunch. What appeared to be flying ants were dispersing from the base of a pine tree. It was fascinating to watch wave after wave of them drift away on a light breeze. I've been studying the flaps of the birds in the videos that I obtained in the Pearl and the Choctawhatchee and noticed something interesting in the hop across the fork. The right wing appears to snap in a whip-like fashion at the end of the downstroke, which is consistent with rapid flaps and wings that are long, thin, and flexible. The easiest way to study this effect is to download the movie and scroll through using the arrow keys on a Macintosh.

11-20-07. We're continuing to analyze the high-pitched calls and will be presenting a talk on them next week at an acoustics conference. In the sonogram of the high-pitched calls, there are two frequency components, which turn on and off at the same time. It's interesting that frequencies also turn on and off simultaneously in sonograms of kent calls from the 1930s. Blue Jay bell calls are much more complicated, with different frequencies turning on and off at different times. I'm not an expert in bioacoustics, but these data suggest that the ivorybill is an unskilled vocalist that can only do the equivalent of strumming a guitar without touching the frets, while the Blue Jay is a skilled vocalist that can play all of the chords.

11-21-07. I've been getting psyched up for a trip out to Tree 5 with the gear sled. Today isn't going to work out because my sore foot flared up again and there are storms predicted. I tested several of the putative kents that are posted at Dan Mennill's web page. In each case, the sonogram contains horizontal "claw mark" features (different frequencies turn on and off at about the same time). The recordings from the Singer Tract and the high-pitched calls that I recorded in the Pearl have the same property. Since Blue Jays are capable of producing the same effect, it's not a reliable way of discerning ivorybill vocalizations, but it's interesting that every putative ivorybill vocalization that I have tested has this property. During an encounter with a pair of ivorybills in the Choctawhatchee, I recorded horn-like notes that don't have this property. They were probably made by one of the deer that passed through the area during the encounter. I asked Dan Mennill about the claw marks. He pointed out that some lines disappear from the sonogram slightly earlier than others and that this may be due to the fact that some frequencies propagate through the forest more efficiently than others.

11-22-07. There are all kinds of Thanksgiving meals. While leaving Stennis to go to a friend's house in Slidell for dinner, I saw a Turkey Vulture feasting on a dead skunk on the side of the road.

11-23-07. I have discovered evidence suggesting that the calls that I recorded on February 20, 2006, are a call that Tanner observed when ivorybills are disturbed. After hearing these calls during encounters on February 18 and 20, I was initially convinced that they were given by an ivorybill since they came from the direction of an ivorybill both times. Ten days after recording the high-pitched calls, however, I obtained a Blue Jay recording in the same general area that has a similar sonogram (two dominant frequencies in each recording). I assumed that nothing could be determined by analyzing such simple sonograms and didn't take a closer look at them. That was a mistake. I recently noticed that both frequencies turn on and off at the same times in the February 20 calls. I then looked at calls from the Singer Tract, the Big Thicket (John Dennis' recording), and the Choctawhatchee and found that different frequencies (even when there are more than two) turn on and off at the same times (some of the weaker calls don't exactly fit this pattern, but this might just be a signal-to-noise issue). After taking a closer look at the March 2 recording, I noticed that the frequencies don't match those in the February 20 recording, the frequencies don't turn on and off at the same times, and there's a good match with a published sonogram of a Blue Jay bell call.

11-24-07. Storms are predicted for the next three days, and I need to finish preparing two talks for Tuesday. So I probably won't make it out into the swamp again until the middle of the week.

11-25-07. Driving into Stennis this morning, I saw a spectacular tom turkey and the first flock of robins of the season. Despite the weather predictions, it seems like a great overcast fall day to be in the field, but I have to finish preparing for the conference.

11-26-07. After listening to many ivorybill calls and studying their sonograms, I get the impression of sound radiating from a vibrating solid object (such as a tin horn). Looking at the massive bills of the birds in the this photo, I can't help but wonder if the bill plays a role in ivorybill vocalizations.

11-27-07. I used to regularly attend conferences of the Acoustical Society of America but hadn't been to many of them in recent years. After hearing that the fall meeting was going to be in New Orleans this year, I decided to submit a paper on the high-pitched calls that I recorded in the Pearl. Although the conference itself wasn't very exciting, submitting the paper turned out to be more than worthwhile because I made important discoveries in the data while preparing the talk and met some contacts that work in bioacoustics. Now that the conference is behind me, I will try to get back out in the field despite the fact that my foot is still giving me problems.

11-28-07. Spending time on my feet at the conference caused my foot problem to flare up. I will take it easy today and try to get out in the kayak tomorrow.

11-29-07. I went for a kayak ride with a friend who is visiting from Washington and showed him the 2006 hot zone. I used the old kayak, which is still useful despite being a bit leaky.

11-30-07. I'm getting caught up with things that I set aside while preparing for the conference. I didn't make it out today but will try to get out at least once over the weekend.

12-2-07. I had a possible sighting in Mississippi this morning. The bird flew into an open area and then rapidly dove down and turned back into the woods. There was white in the right places on long and thin wings. This was near the edge of the Stennis buffer zone in an area with a mixture of pines, hardwoods, and cypresses.

12-3-07. I have identified an area that has much in common with the 2006 hot zone, including being secluded. I was planning to visit the area today but decided to wait for the gusting winds to die down. After working late last night, I walked out of the building in the dark and saw quite a sight after sitting down in the car and turning on the headlights. An impressive buck was lying right in front of the car. It never moved as I slowly backed out of the parking spot. Near the location where I had the possible sighting, there's a stand of dead trees, which is one of many that are within a short ivorybill flight of the Pearl. If the ivorybills are concentrating on this widely scattered food source, it will be almost impossible to have anything other than the occasional sporadic sighting.

12-4-07. It's a beautiful day, but I've decided to wait until Thursday before getting back out in the field. The podiatrist instructed me to stay off my feet as much as possible for three weeks. That period will be over tomorrow, when I am scheduled to see him again. After going outside at lunch time, I could no longer resist the urge to get back out in the kayak. I visited the promising area that I mentioned yesterday. This area has more woodpecker activity than the 2006 hot zone, the habitat is similar, and it's even more secluded. I found this cypress, which might be just tall enough at 80 feet to provide a good view over the surrounding area. I was surprised to see a water moccasin sunning on a fallen tree this late in the fall.

12-5-07. The doctor checked out my foot today. The good news is that it seems to be getting better. The bad news is that I'm supposed to continue to limit my activities for another month. I can't afford to just sit around with my foot propped up, but I'll try to go a little easier than I did before the problem arose.

12-6-07. I have recently been exploring this secluded waterway, which reminds me a lot of the 2006 hot zone. Since it's just a short flight from that area, it seems likely that the ivorybills have visited it over the years. This morning, I found this nice little plant community at the end of a fallen tree that hangs out over the water.

12-7-07. I'll be tied up in the office most of the day but might get out late in the afternoon. I visited the tallow trees yesterday and found them loaded with fruit (popcorn as the locals call it), but there still aren't any birds feeding on them. Last year, many woodpeckers and other species were seen feeding in the tallows in late December and early January, and an ivorybill was seen in the area on December 20.

12-8-07. There's something that I love about a foggy morning in the swamp. I was eager to get an early start this morning after looking out and seeing the fog. It was interesting to watch a pileated foraging near the top of a sweetgum.

12-9-07. I visited the 2006 hot zone with a birder from Illinois. We noticed that someone has been making trails using a chainsaw. It's unfortunate to see such illegal activities in an area with a critically endangered species. It's interesting how many of the trees that came down during Katrina and landed in the water look like this one. Notice that long branches go deep into the water and prop the tree up above the water while most of the branches on the other side of the tree are small. This may be entirely due to the fact that branches tend to be longer on the open side of a tree that faces the water, but another possible factor is that a tree might tend to rotate while falling so that the side with the largest branches leads the way.

12-10-07. I decided to stay in today and let the visitors from Illinois be my eyes and ears in the field. They visited the area that I recently started watching closely, saw lots of woodpeckers, and agreed with my assessment that the habitat looks promising. A visitor from Georgia reminded me that he heard high-pitched calls in the Pearl earlier this year. You have to be careful about these calls since the Blue Jay bell call is similar, but he caught a glimpse of a large bird just before the calls started. If you hear something that sounds like bell calls and there's no sign of a Blue Jay, I would recommend firing up the video camera and switching over to full-alert status.

12-11-07. I'm going to be tied up in the office for the next day or two. I asked the birder who heard the high-pitched calls for more details. The date was January 31, 2007. The location was a short distance from the 2006 hot zone but on a different waterway. After hearing the calls for several minutes, a large bird that appeared to be a woodpecker flew from the direction of the calls and disappeared behind trees. There were no more calls after that, and the bird was not seen again. Another birder was visiting from Idaho during that period, and he heard kents on February 5, 2007, near the area where I had my first sighting on February 2, 2006. That location, the 2006 hot zone, and the location where the birder from Georgia heard the high-pitched calls form a nearly equilateral triangle with sides a little less than a kilometer. Not far from there is an area that I have dubbed the Bermuda Triangle, where I broke my arm, capsized the kayak, had a close encounter with a gator, and nearly stepped on a water moccasin.

12-12-07. I'm stuck in the office again today.

12-13-07. It was raining this morning, and then I got tied up in the office this afternoon. So I won't make it out into the swamp today.

12-14-07. I'm still tied up in the office, but we have a trip out to the tall trees planned for this weekend if the weather permits. The top of the tallest tree in the swamp is not the place you want to be when a thunderstorm hits.

12-15-07. Gretchen and I rigged Tree 7, which is in the area that I recently started monitoring. After noticing several wasps, we decided to stop climbing a little lower than planned. The view is marginal from that height, but it should be pretty good at the top. It was very windy up there, and the tree was swaying despite being a very sturdy cypress.

12-16-07. After slogging through the swamp yesterday, my foot is now throbbing again. It looks like I'm going to be restricted to the kayak for a while. I'll have to let my foot recover for a few days before getting back out there.

12-17-07. One of my friends has a poster-sized copy of a high-quality photo of the Pearl. There's no legend on the photo, but it's clearly not the visible spectrum. Different tree species show up in different colors, and cypresses really stand out from other species. Individual trees are resolved, and several of the cypresses that we have climbed show up in the photo. The mother of all cypress groves is lined up in a row that runs for a few miles through the most remote part of the Wildlife Management Area. I've seen part of this grove from Tree 5, but I hadn't realized the extent of it. It seems to be an ideal location for a roost, and Tree 5 provides an excellent lookout point for monitoring birds flying between that grove and the hardwoods. I forgot to mention something about the tree that we climbed a few days ago. On the way up, I noticed a large cavity that was under construction. The chisel marks appeared to be about twice as wide as typical pileated chisel marks. This is one of the trees that stands out in the photo. It's one of the few large cypresses in that area. I didn't measure the chisel marks since I wasn't expecting to find them and didn't carry anything up the tree for measuring (including reading glasses). It's nice to be able to inspect cavities from up close.

12-18-07. I'm going to be tied up in the office for a few days, but I will try to spend some time in the kayak. While studying the photo of the Pearl, I found the cypress that I saw an ivorybill swoop up into on October 21, 2006. It's the most prominent tree in that area. I would like to hike along the full length of the cypress grove and check for cavities, but my foot might suffer permanent damage if I try it now.

12-19-07. A local birder reported seeing a female ivorybill in the pines a little over a mile to the north of where I had a possible sighting a few weeks ago. There are many stands of dead pines in that area. The sighting was in late June, which is consistent with Stoddard's observations of ivorybills in pine forests during the summer and fall. A friend saw a raccoon with a large can stuck on its head yesterday here at Stennis. The poor animal must have found a little food left in the bottom of the can. The can was stuck on fairly tight and completely covered the raccoon's head, but my friend was able to pull it off.

12-20-07. I visited the area of the June sighting. The habitat is poor in that area, but the bird was flying from a direction where there are lots of dead trees. One of these days, I need to take a flight over the pines in and around Stennis and look for large stands of dead trees. Searching in the pines doesn't seem promising, but a look from the air might provide some ideas. I got the idea for climbing cypresses while crossing the I-10 bridge at the Louisiana-Mississippi border. At first, I wished that I could stop on the bridge and watch from there, but then I saw several cypresses towering over the surrounding trees.

12-21-07. It was one of those foggy mornings that I love to spend in the Pearl, but I was tied up in the office again. This fall, I missed a lot of days in the field due to a bad foot and a heavy work load in the office. Winter begins tomorrow, and I will be picking up the pace over the next several weeks whether my foot cooperates or not.

12-22-07. I visited the tallow trees this afternoon. They're loaded with food, but I still haven't seen any birds in them. They must be late this year.

12-23-07. Unless a big truck is passing, I always look out over the Pearl from the I-10 bridge, which provides a spectacular view that only lasts for a few seconds at highway speeds. Now that I know the location of the big grove of cypresses, I looked out in that direction and spotted some huge trees. A few of them appear to be taller than Tree 5. I'm really excited about the cypress grove. Last year, I heard a series of loud pounding sounds coming from that grove. It was the only time that I have heard anything that I would attribute to an ivorybill working on a cavity or foraging. I haven't done much searching for cavities in the Pearl, but now I have a good place to look. Most of the large cavities in the Choctawhatchee were found in cypresses.

12-24-07. I visited the pine forest near the northeast corner of Stennis. People rarely visit that area, which often has lots of birds. There were lots of sparrows and robins, but the only woodpecker was a pileated. I went for a walk on even terrain, and my foot held up fairly well.

12-25-07. I was planning to spend some time in the kayak this morning, but it was raining.

12-26-07. I took a long kayak ride this morning and visited the 2006 hot zone and the Bermuda Triangle (the area where I've had several mishaps). I heard loud pounding noises in the woods, but it seemed to be someone using a hammer. Right after that, I heard something with loud wingbeats fly across behind me. I have obtained a precision compass that will allow me to pin down the locations of tall trees and also to measure distances in situations when there is no line of sight (e.g., the distance between where the ivorybill flushed and the fork deep in the woods where it appears in the video).

12-27-07. On the way back to Waveland last night, I observed an interesting effect in the sky. A thick layer of clouds was moving in from the east with a sharp front that gave the impression of a retractable dome covering a baseball stadium. The cloud layer was so thick that it completely blocked the light of the Moon, which had just disappeared behind by the front. The interesting effect was that the clear sky ahead of the front appeared blue. I don't believe I had ever seen blueness in the night sky before. In this case, the blueness (caused by scattered moonlight) was easy to see with the direct light of the Moon being completely blocked. This is somewhat analogous to the solar corona being visible during an eclipse. The blueness of the sky was obvious beside the contrasting deep black of the clouds.

12-28-07. Since storms are predicted for the next few days, I will probably stay in the office and get some work done. I have some ideas for checking out the cypress grove and hope to try them out in the next few weeks. The timing will depend on when I can get help from visitors and a boat ride to a convenient access point.

12-29-07. I visited the 2006 hot zone to take some measurements. I love the new Suunto KB-14 compass. It gives precise readings, which I double checked for consistency. I used the compass and the laser rangefinder to determine that the distance between the snag from which the bird flushed and the fork in which it appeared near the end of the video is 218 m. I also determined that the fork is about 77 m deep in the woods and that the bird initially flew about 60 m to the position where it appeared through a gap in the vegetation. The distance between the position where I obtained the video and the fork is 128 m. I previously estimated some of these distances by GPS, which didn't provide the accuracy that I expected (perhaps due to tree cover).

12-30-07. A thunderstorm that started last night continued until well after sunrise this morning. The duration was unusual, especially for this time of year. I'm considering a kayak trip to the tall trees tomorrow, but I might change plans since currents can be formidable along that route after a winter storm.

12-31-07. Something came up in the office that I had to take care of this morning. So I changed my plans to make the trip out to the tall trees and visited the pines south of Stennis. There wasn't the slightest ripple on this pond, which is near the spot where a biologist saw an ivorybill in 2002. The photo may seem confusing unless studied carefully.

1-1-08. It was too windy for kayaking or tree climbing. I'll take the day off and watch a little football with a friend in Slidell. I'll check the tallows on the way over there. It seems that the fruit should be ripe by now. I passed by the tallows. A few passerines were feeding in them but there are still no woodpeckers.

1-2-08. I visited the tallows twice today, but there still wasn't any activity. I decided not to go out in the kayak since it was cold and windy. It's supposed to be even colder tomorrow, but it'll be fine if the wind dies down.

1-3-08. It was still windy this morning, and the temperature got down to the low 20s. Since any kind of kayak incident could be serious in such weather, I decided to stay off the water again. I did some exploring in pine forest at Stennis that borders on the swamp near one of the trees that we have rigged. That area seems promising since it's closed to the public, isolated from human activities, and not too far from the 2006 hot zone.

1-4-08. I visited the Honey Island Swamp to check out an area where a local birder heard something similar to the sequence of taps in the Singer Tract recording. What made this report really intriguing is that a pileated flew in during the tapping and gave territorial calls. Pileateds here in the Pearl are a lot smarter than many humans in that they know that ivorybills exist, and they can get feisty when ivorybills encroach on their territories. On February 16, 2006, I heard three kents that were immediately followed by stern territorial calls from a pileated. I saw a Red-headed Woodpecker, which is rarely seen in the interior of the Pearl. The weather is finally warming up after the bitter cold spell.

1-5-08. I spent the morning in the kayak. It was warm enough to go without a jacket. I thought about going up one of the trees, but it was too windy.

1-6-08. I did some exploring near the Mississippi coast this morning and noticed birds (including woodpeckers) feeding on the tallows there. Since the foot problem flared up again, I decided to spend the rest of the day getting caught up on things in the office.

1-7-08. I only had time for a short visit to the area south of Stennis today. I took a photo that explains the photo that I posted on December 31. The explanation is posted here.

1-8-8. I might not get a chance to go out in the kayak today, but I have some interesting comments to pass along from a naturalist who saw an ivorybill in South Carolina many years ago. A timberman in that state told him an interesting tidbit about his observations of this species. After an ivorybill flushes, it will "sometimes reappear at some distance by steeply swooping up a tree parallel to the trunk." That is exactly what can be seen in one of the video clips that I obtained in Florida. About eight seconds after the bird flew to the right from behind a tree, a bird (perhaps the same one) swooped up very steeply and parallel to the trunk of a tree off to the right.

1-9-8. I took a nice kayak ride into the 2006 hot zone this morning. There was lots of bird activity, including an unusual number of swallows. A few months ago, I was given a copy of Richard Pough's report from the Singer Tract. I was asked not to circulate this important and rare source of first-hand information. Although copies have started circulating, I will continue to honor the request but will mention something interesting in the report that provides insight into the difficulty of finding ivorybills. During 46 days of intensive field work, Pough observed a lone ivorybill (perhaps the same bird that Eckleberry observed later in 1944) that spent most of its time in an area on the order of a quarter of a square mile. In river basins such as the Pearl and the Choctawhatchee, there are hundreds of parcels of that size where ivorybills could easily remain undetected for long periods.

1-10-08. With severe storms predicted, I decided to stay in the office today. Nice weather is predicted for tomorrow, and we're planning a trip out to the tall trees. Now that the leaves are down, the tree nearest the large grove of cypresses should provide a good view of those trees. I'm looking forward to using the precision compass to start taking data on the locations of the taller trees in the grove. Combined with the image that shows the crowns of individual trees, it should be possible to pin down locations without range information (the laser rangefinder doesn't work at such distances).

1-11-08. The tree climb has been postponed until tomorrow. This afternoon, I visited the tallows near where there was a sighting a little over a year ago, but there's still no feeding activity in those trees. Later on, I found a pileated feasting in a tallow at Stennis.

1-12-08. Gretchen and Tasha joined me for a gorgeous morning in the swamp. We climbed Tree 2, which is back in this bayou. Lots of birds flew by this morning, including vultures, a kestrel, a flock of blackbirds, a heron, and cormorants. We heard lots of woodpeckers and a Barred Owl from the top of the tree. An Osprey can be seen in the foreground of this photo of Tree 5. I used the precision compass from up in a tree for the first time and got the bearings of several trees and landmarks. We discovered a convenient practical use for the compass; after I determined the bearing of Tree 5, it was easy for Gretchen and Tasha to use the compass to make sure they were looking at the right tree. Now that the leaves have fallen from trees in the foreground, many trees in the large grove of cypresses can be seen from Tree 2, and some of them appear to be over 90 feet tall. The compass was useful for pinning down some tall pines near the 2006 hot zone. During previous climbs, I thought I had the right trees. Now I know for sure. I got the bearing of what I thought might be Tree 3, and it checks out. This panorama shows part of the big grove several hundred meters in the distance. Some of the trees appear to be much taller than the 73 foot vantage point in Tree 2 where the photo was taken.

1-13-08. After spending several hours in Tree 2, I'm a bit achy and fatigued. It's a good day for resting the body and getting some work done in the office.

1-14-08. I spent the afternoon out in the kayak and got back just as it was getting dark. It was nice to experience dusk out in the swamp for a change. I heard a loud single rap near the 2006 hot zone just after sunset. The Barred Owls have become very vocal and were calling throughout the afternoon.

1-15-08. There's an interesting article in the December 23 edition of the Times-Picayune on the recovery of habitat since Katrina. The article mentions an estimate by scientists at Tulane University that approximately 320 million large trees were killed or severely damaged along the Gulf Coast. With such a broad and massive swath of dead trees, it's no wonder that sightings (other than a brief flurry in the 2006 hot zone) have been sporadic and widely spaced. I've been thinking about Geoff Hill's video of a bird flying low along the bank (the one in which the reflection of the bird off the water shows lots of white). Later in the morning that I got the Pearl video, I saw a large bird flying low a short distance back in the woods from the bank. I thought it was an ivorybill but didn't get a good enough look. Two days before that, I sat in the kayak while an ivorybill called from just behind a fallen tree. It seemed unusual that the bird was able to get out of that position without being seen. Perhaps it flew low along the ground like the bird in Geoff Hill's video. I spent another afternoon out in the kayak. The past few days have been absolutely bayoutiful. A Bald Eagle was soaring high over the Pearl. It was entertaining to watch several waves of Black Vultures returning to their roost.

1-16-08. My bad foot needs a rest, and it's a rainy day. So I'll be staying in the office.

1-17-08. I took a long kayak ride this morning and went all the way past the Bermuda Triangle (there were no unfortunate incidents in that area this time). I found some fresh foraging sign that looks very interesting. There was quite a bit of it, and it looks like it was done all at once. This isn't far from where a birder recently heard double knocks.

1-18-08. Going over the I-10 bridge as a passenger, I used the precision compass to get the bearings of one of the largest trees and a thick clump of trees in the big grove of cypresses. I went by the tallows again, but there was still no feeding activity. I also spent some time in the Honey Island Swamp.

1-19-08. It was another rainy day that I spent working in the office.

1-20-08. I visited the 2006 hot zone and was planning to also visit the Bermuda Triangle, but the water was a bit low. It was a nice day despite being a bit cold and windy.

1-21-08. I spent the day in the office in order to get caught up with things before paying a brief visit to the Choctawhatchee. Now that the leaves are down, I want to return to the area where I got the video last year and take some measurements.

1-22-08. Since the water was high, I paddled out to the Bermuda Triangle this morning. I'm planning to drive to the Choctawhatchee this evening and might not be able to post updates for a day or two.

1-23-08. I spent the morning paddling to the site where I obtained video clips a little over a year ago in the Choctawhatchee. I wanted to inspect the tree from which the bird flew in the video, take measurements, and get photos. I tried to do this in April, but the tree was hidden by leaves. Although high water prevented me from getting the job done on the second attempt, I heard a nice double knock on the way out there. I took along two photos and the coordinates of the site, but it turned out that this information wasn't sufficient. The water was so high that the entire forest was flooded. It was tricky getting back there with the current flowing through the forest as shown in this paddle-cam image. I used the GPS to navigate to the site, but the key landmarks in the photo were submerged. Having studied the video extensively, I recognized a few landmarks higher in the scene, but they weren't sufficient to find the tree (which I fear may have fallen by now). I tried moving around in the kayak and looking to the east in hopes of spotting the tree, but this was difficult in the strong current. On the way back, I was surprised to cross paths with Brian Rolek way out there. He said the water was as high as he's ever seen it. Shortly after talking to Brian, I came face to face with a Water Moccasin that was coiled around a tree branch (very much like the medical symbol). Back at the landing, I had a nice chat with Rob Tymstra and two other ibwologists. I would advise any birders venturing into the Choctawhatchee to be very careful during high water. This river is always dangerous due to the strong currents. When the water is this high, it's easy to get lost out there. Despite having spent some time in the area, I was anxious about finding my way back. I'll give it another try when the water goes back down. This was my first time on the highway with the kayak on the Honda, which has two convenient places to hook lines under the front bumper. It rode very nicely up there.

1-24-08. Water, water, water. Yesterday, it was flooded in the Choctawhatchee. Today, there's a steady rain in the Pearl. It was disappointing to fail to get the job done yesterday, but the tree that I wanted to find appeared to be more than 100 meters from the observation position, and it was only visible from a certain position between the trees in the foreground (the tree only shows up at certain times in the video as the kayak drifts around). Making sure you have the right tree is like peeking through a keyhole. Everything needs to be lined up just right. When I tried in April, the leaves were in the way. With the water flowing rapidly and key landmarks submerged during the latest attempt, I wasn't able to maneuver the kayak into the position of the keyhole. I'll give it another try soon. It's always interesting to visit the Choctawhatchee, and it's only about 250 miles from the Pearl. There's a huge cypress right next to the observation position. Since the sighting was shortly after dawn, that tree is a good candidate for a roost site. According to a NOAA web site that posts water levels for the Choctawhatchee, the water was right about at the level corresponding to "extensive lowland flooding" during my visit.

1-25-08. The air was a bit icy today, and I began to feel it after sitting at a stakeout near the Bermuda Triangle and getting caught in a light rain. I've obtained a wonderful article by Bayard Christy that was published in Audubon magazine in 1943. The article contains a rare first-hand account from the Singer Tract. It's the only historic account that I have found that mentions anything about the flaps of an ivorybill at takeoff, and the account is right in line with the videos that I obtained in the Pearl and the Choctawhatchee. He also describes repeated swooping very much like what I observed in the Choctawhatchee.

1-26-08. It rained this morning, and I'm going to spend the afternoon getting caught up in the office.

1-27-08. This morning, I made the rounds at Stennis, which I hadn't done for a while, and discovered an overgrown trail that leads to the vicinity of Tree 7. I visited the overgrown canal where I heard kents eight years ago at about this time of year. This photo was taken while standing on the bank of the canal and looking toward the location just beyond the opposite bank from which the kents were coming. This photo shows something interesting at the spot from which the kents were coming. The small tunnels were made by bees or wasps. This photo of the same spot was taken in April 2006. I have observed the tunnels many times over the past few years and have seen the insects working on them. The tunnels get exposed when the hill erodes. If these tunnels contain larva during the winter, it's possible that they were exposed during an erosion event, and that is what attracted an ivorybill. My first thoughts of climbing something to get a view out over the Pearl involved this tower. The walkway is 137 feet above the ground. While visiting the tower, I took a GPS reading that is consistent with a bearing measurement that I took from 5.3 km away in Tree 2.

1-28-08. A few weeks ago, I mentioned Richard Pough's account from the Singer Tract. Now that copies have begun to circulate, I have decided to post the excerpts that follow. This account provides hope that the ivorybill will have a good chance of recovering if habitat is protected, and it's consistent with this cartoon and the accounts of many observers over the decades and in recent years. The only inconsistency is Tanner's dogma, which is wrong.

"The area has in the past been frequently referred to as entirely or largely covered by virgin forest. This is not true, especially in the case of the forest types occurring on the higher lands."

"Maps of the area as of 1846 showed much of the Tensas River Bank in plantations and many cleared fields back from the river on some of the interior ridges. This development continued until the Civil War, by which time Madison Parish was producing 110,000 bales of cotton a year. As the Parish has never produced over 30,000 bales since the Civil War, one gets some idea of how much land is now occupied by second growth forest of approximately 80 years age."

"It is often difficult for the untrained eye to distinguish a virgin from a second growth forest in this part of the country, where trees grow with such amazing speed. To cite an example, the growth rings of one 40" diameter water oak which had grown in the open revealed it to be only 30 years old."

"I must confess that the ivory-bill problem puzzles me exceedingly, and I do not feel that Tanner's report begins to explain the reasons for the drastic decline in this species. Despite the fact that he started his studies in the area before any extensive cutting had taken place, and had an unusually competent local woodsman to help him, he found only one nesting pair and their young, and so far as I know, actually saw and studied only one other bird (a lone male in the Mack's Bayou area)."

"I suspect that the ivory-bill has never been a sedentary species. It seems to me entirely possible that no forest, virgin or otherwise, normally has a large enough, concentrated enough and continuous enough food supply for them to be permanent breeding residents. It is, I believe, a mistaken impression that in an all age class virgin forest, trees die at a more or less uniform rate. Certainly, this is not true here in the Tensas River bottomlands. Periodically fire and, even more important but less frequently, drought initiate a wide-spread dying off of the mature and over-ripe trees. These die and fall in a relatively short period, which is often followed by a rather long period, during which those trees healthy enough to survive continue to grow, with little mortality."

1-29-08. I'm planning a visit to the cypress grove tomorrow with two other searchers. We will look for cavities and unusually tall trees and will get plenty of photos and video. Our goal is to survey the grove in one or two visits in order to minimize disturbances in case there's an active cavity. I have recently been re-reading articles that I originally read before starting the search and have been finding some interesting tidbits. I noticed that John Dennis made some interesting comments about the crests of the ivorybills that he observed in Cuba that are consistent with the appearance of the crest of the bird in the Pearl video.

1-30-08. Two other searchers joined me in a visit to the big cypress grove. We found several trees that are comparable to Tree 5 as well as several large cavities, including a fresh one. I computed the heights of several of the cypresses. Seven of them are taller than Tree 5, and one of them exceeds 100 feet. All of them have "bomber" branches near the top that would make them excellent for climbing. There are even taller trees that can be seen from the I-10 bridge, but we didn't find them this time. I had a bad fall and caught myself with the arm that I broke last year. It was a severe jolt to the arm, but it held up. I dropped my watch in ankle-deep water, but we weren't able to find it in the mud. I can barely walk on my bad foot, which was throbbing toward the end of the hike. I'll be restricted to kayak duty for a while.

1-31-08. I have prepared vertical panoramas of trees that are 102 and 96 feet tall. These trees appear to be very healthy, and they're mixed in with other tall trees. This cavity is approximately four inches in diameter (the diameters of the red circles are four and five inches). The vertical diameter appears to be less than four inches in part due to the viewing angle. It's interesting how this branch fell on a fallen tree and broke in half.

2-1-08. A violent storm last night was followed by a gorgeous day in the Pearl. Some of the resident birds have started singing. I visited the 2006 hot zone and saw lots of woodpeckers, including this sapsucker.

2-2-08. I took the day off to get caught up on chores, such as changing the oil in the Honda. While doing some housecleaning of the video files on my computer, I produced this clip of a pileated from footage that I obtained in the Pearl last year.

2-3-08. I visited the 2006 hot zone and discovered who's been using a chainsaw up there. A hog hunter has opened up a long stretch of a waterway that used to be isolated from boat traffic by fallen trees. The motive for this senseless (and illegal) act was to get to an area that can easily be reached on foot from the other direction. This isn't the only threat to the Pearl ivorybills. A few days ago, I heard machine gun fire coming from the live-fire range for the first time. When I photographed a nice looking cavity a few days ago, I measured the distance with the laser rangefinder (as usual) but also measured the inclination angle (since we were interested in the height). From my vantage point, the cavity was 34.5 degrees above the horizontal, which reduces its apparent vertical size by about 18 percent. Using the range information to scale the image and using the angle information to stretch it in the vertical direction, I obtained this comparison, in which the red circles are four and five inches in diameter. This is the most impressive cavity I have seen. It looks like it was recently made with woodworking tools in a live cypress that isn't hollow.

2-4-08. I'm scheduled to present a talk on my work in the Pearl in Sarasota at the end of the month. I have a lot of material to get organized and decided to get started on it. So I didn't make it out in the field today.

2-5-08. Since the water was high, I decided to take a kayak ride out to the Bermuda Triangle. Strong gusts of wind started up just after I arrived in that area, and I turned back in order to beat the storms that are predicted for this afternoon. There was a good deal of pileated activity this morning. I saw or heard eight of them on the way out. I sat near the bank and listened for a while shortly before turning back, and a Barred Owl flushed from nearby. It moved a short distance away and didn't seem to mind my presence. I kept hearing a high-pitched call that resembled the alarm call of a chipmunk. I don't know what was making it, but it might have been reacting to the owl.

2-6-08. It was a spring-like day. Leaves and flowers are already starting to come out, and the birdsong has really picked up. I visited the 2006 hot zone and had a nice drift back with the current.

2-7-08. This afternoon, I finished preparing a talk that I'll be giving in Sarasota at the end of the month. For the talk, I took photos of some of the gadgets and gear that I've been using in the Pearl. The gadgets include the GPS, laser rangefinder, clinometer, and precision compass. A GPS is essential for marking locations, navigating to specific points, and avoiding getting lost. The rangefinder has many uses, including measuring the heights of trees and distances to objects. The clinometer (which was donated by the finder of the world's tallest tree) is used to measure the elevation angle of an object above the horizon. This device is essential for measuring tree heights. The precision compass makes it possible to measure the bearing of an object to a fraction of a degree. This device is useful for estimating the coordinates of objects (such as trees) and can also be used along with the rangefinder for measuring distances by trigonometry when there isn't an unobstructed line of sight between two objects. The climbing gear (which was donated by an anonymous biologist) includes a harness that is worn around the waist, ascenders that only slide in one direction along the climbing rope, leg straps attached to one of the ascenders (the legs do most of the work when climbing), a grillon (the long red line) for safely tying yourself in at the top of the climb, a gri-gri (the small device in the lower right) for safely descending, climbing rope and rope bag, and a foldable cube that is very useful when reeling in or out lines and ropes.

2-8-08. It was another bayoutiful morning in the Pearl. I saw my first otter of the season. The water levels and currents are both decreasing. If the same is happening in the Choctawhatchee, I will soon be going over there for another visit.

2-9-08. I paddled out to the 2006 hot zone and spent a few hours hanging out and enjoying a gorgeous day. It was interesting to watch a pair of Red-bellied Woodpeckers make repeated trips to an American Holly tree for berries. The Barred Owls have been very active lately. This morning, I noticed that activity has suddenly picked up in the Yaupon Holly trees.

2-10-08. One of the visitors went out with me to climb two cypresses in the big grove. After getting about 60 feet up the first tree, I noticed a spectacular tree a few hundred meters to the west. That tree is about 110 feet, and I climbed up to 94 feet. It was my highest climb by far and the tallest cypress that I have found in the Pearl. It might end up being my last climb. The device that I use for descending is called a gri-gri. It securely attaches you to the rope, and there's a lever to pull to gradually (supposedly) belay yourself down. When I first started climbing, the gri-gri seemed to work very smoothly, but then it started having problems with the rope getting jammed. I ordered a new gri-gri and tried it out today, but it was even worse. The rope got jammed when I was still way up there. Then it suddenly gave way, and I went into an alarming free fall for about three feet. When this happened, I instinctively grabbed the rope with my right hand and suffered nasty rope burns. I had several of these hair-raising events on the way down. I'll try to figure out what's causing this problem, but I'm not sure about doing any more serious climbing after this experience. While up in the tree, I took this photo looking down, this photo of some of the big trees nearby, and this photo that shows many of the cypresses in the big grove as well as the rocket towers about six miles in the distance at Stennis.

2-11-08. Having too many aches and pains to go out today, I limited myself to putting together panoramas from Tree 0 (the 110 foot cypress) looking toward Stennis and in the opposite direction. Since the camera was held at 94 feet, the trees that break the plane of the horizon are over 90 feet. Some of the trees nearby are over 100 feet. This photo shows the view looking straight down from 94 feet.

2-12-08. I'm continuing to nurse the rope burns and rest my foot, which always hurts after marches through the swamp (but it wasn't as noticeable this time due to the other aches and pains). I have determined that the descent problem is due to the rope. The problem started after the rope fell in the mud. Although I soaked it in water, it's possible that dirt was trapped inside the sheathing. It's hard to keep gear clean out in the swamp. I have two other ropes, but it might be possible to have the bad one cleaned.

2-13-08. I broke my arm a year ago today. I'm very thankful that it healed straight and strong and that the wrist is fully functional and flexible. I'm sure this is largely due to the fact that a plate was installed to line everything up. I was eager to go out in the kayak today, but the winds were too strong. During the tree climb on Sunday, I saw an interesting thrush-sized bird foraging nearly 100 feet up in the crown of a nearby cypress. The facial pattern (naked eye view) and streaks on the sides of the breast (seen well through binoculars) were consistent with a female Black-headed Grosbeak. It flew to another tree before I could get a good look at the head, and I experienced one of the disadvantages of birding from a tree when I wasn't able to move horizontally and follow it. I have run the climbing rope through the washer twice using ordinary laundry detergent. I'm going to do some practice climbing to make sure everything is working properly. I'll break out one of the other ropes if necessary. The climbing experts and I have invested too much into this effort to give up on it now, and I believe it has an excellent chance of success. I only wish that I could get a few other climbers up there at the same time in widely spaced trees.

2-14-08. I went for a nice kayak ride this morning, but my right arm was snapping and popping while paddling (similar to when scar tissue was breaking away in my left arm last year). This might have something to do with grabbing the rope during the free fall the other day. I saw a kestrel and a creeper, which I don't see very often in the Pearl.

2-15-08. It was nice to spend two days in the field with the university searchers, who have completed their work in the Pearl. Both days were very productive, and they were my first explorations in the big grove of cypresses. We found some very interesting cavities, a surprising number of cypresses over 90 feet, and one incredible cypress that is about 110 feet. One of the searchers saw a White-tailed Kite a little to the north of where I saw one last year on January 6. I'm not aware of any other sightings of that species in the Pearl during the past few years. Although there's no way of knowing the number of days that species has been present during the past two years, this is a good example of how a rare species can go undetected for long periods in a large river basin. I was hoping to make it out in the kayak but got tied up in the office all day. One group of visitors has departed, but another group has arrived, and we have lots of plans for the next several days.

2-16-08. There were five of us in the field today. Late in the afternoon, three of us had an interesting sighting near a large cavity that I found in a sweetgum last year. I picked up the bird first and got my binoculars on it. It was black with lots of white on the wings. I noticed a large white patch on the trailing edge of the dorsal surface of the right wing. The other observers didn't see field marks, but we all noticed a rapid gliding flight. I noticed the bird rock from side to side as it maneuvered to land. One of the observers fired off a high-resolution photo but missed the bird. The other observer saw the bird swoop down when it took off.

2-17-08. We returned to the area of the sighting and got caught in a severe thunderstorm. After dodging lightning bolts and hail stones on the way back, we reached the shelter of the cars just as it stopped.

2-18-08. Four of us split up into two teams and covered about 25 miles today by water and foot. We're tired and going to head to Waveland for BBQ.

2-19-08. In the same general area as the possible sighting, we heard a series of kent-like calls, and Richard Martin recorded 17 of them (my camera was inoperable due to moisture condensation at the time). The calls don't have a strong metallic quality, but the source was far enough away (perhaps a few hundred feet) for the higher frequencies to be attenuated by vegetation. The sonograms of these calls have similarities to the sonograms of known and putative kents. We returned to the "warm zone" this afternoon, and I heard two distant kent-like calls.

2-20-08. I returned to the warm zone and heard three more calls from the same area. I didn't stay long because I've gotten sick and was making too much noise by coughing. This has been such a busy week that I hadn't gotten around to taking GPS readings until this morning. It was interesting to find that the locations of the sighting and the calls are only 240 meters apart, and they're along the same waterway. This wasn't obvious before consulting the map because we approached these areas from different directions. It's difficult getting around out there because of blackberry patches that are thick enough to secure the perimeter of a P.O.W. camp.

2-21-08. I've got a cold and it's a rainy day. I'll stake out the warm zone later if there's a break in the weather. I was going through some high-definition video that I took while driving over the I-10 bridge last year and noticed this image that shows a cypress (on the horizon and about three quarters of the way across the image) that appears to be about 120 feet tall. I've made two trips out to that area but have not yet managed to find that tree. The rain let up late in the afternoon, and I visited the area of the recent sighting. I stayed until dusk and noticed bats for the first time this season.

2-22-08. I visited the site where the calls were recorded but didn't have any luck. It was muggy and the skeeters were out in force. When we heard the calls the other day, my camera wasn't functioning due to moisture condensation.

2-23-08. The visitors kept me on the go this week, and I got sick after getting caught in a downpour. With a long drive to Sarasota coming up next week, I decided to take it easy today. Although the two calls that I heard late on February 19 were weak, one of them shows up fairly well in a sonogram and has a similar signature to the calls that were recorded that morning. I heard three similar calls in the same area the next morning, but there hasn't been anything since then. I wanted to clarify some details of the sighting on February 16. The bird glided in at high speed on fixed wings. I got binoculars on it and noticed that it tilted from side to side as if adjusting for a landing. I noticed a large white patch on the trailing edge of the top of the wing just before losing it in the trees. The bird came in from an angle such that it probably didn't see us at first, and the lighting was excellent. It might have been a spectacular sighting if I had been a little faster with the binoculars. I'm encouraged by the locations of the sighting and the calls relative to each other and to the 2006 hot zone. We have a tree rigged not too far from this area.

2-24-08. This morning, I recorded the two calls in the top sonogram in this image. It was clear that these were Blue Jay calls, and in fact I saw the bird that was making them. The lower sonogram corresponds to the calls that Richard Martin recorded on February 19, which have a Blue Jay quality as well as kent-like characteristics. The calls that were recorded today lack variations in pitch (like kents), but the frequencies turn on and off at different times (unlike kents and the kent-like calls that were recorded on February 19). Since the frequencies match in the two sonograms, it's now clear that the February 19 calls must have been made by a Blue Jay.

2-25-08. I'm making final preparations for the trip to Florida this morning but hope to make it out this afternoon. During a recent visit, Richard Martin obtained this photo of a pileated flying near the forked tree in the Pearl video (Richard believes the pileated was just on this side of the tree). It would be very interesting to get a photo of a pileated perched in that tree. I went for a walk in the Pearl this afternoon and came upon a cottonmouth on the trail. I'm leaving for Florida tomorrow and should be back to the Pearl in less than a week.

2-26-08. I spent the day driving to Tampa. It's always interesting to cross the Choctawhatchee, Chipola, Apalachicola, and Suwanee. It's depressing to see all the development that has occurred in Florida since I moved here in 1965. A friend is going to take me in his boat to an area where his father saw an ivorybill in the 1950s. I'm also planning to visit the Hillsborough River, where we always went to escape the heat of summer many years ago. I'm eager to see "The High Cypress," which had a nice fork 50 feet up for jumping into the river. I sure hope it's still standing.

2-27-08. I went to check on "The High Cypress," which we used to jump out of many years ago. The water is higher and the scene has changed, but I'm pretty sure that I found the right tree. Part of the top has broken off, but I recognize the curvature, the stub of a broken branch, and the large fork, which was 48 feet above the water when I measured it in 1974. We would also jump from a branch to the right that was 52 feet up but is now gone. It was a thrill to hear the air rushing by when jumping from that height. I waded through this swamp to get to the edge of the Hillsborough River near our old house.

2-28-08. I had a wonderful visit at the Tree Foundation in Sarasota, where I met Margaret "Canopy Meg" Lowman and her students and gave a talk on my work in the Pearl to an enthusiastic audience. Meg has done pioneering research in tree canopies around the world and has really been an inspiration for my work in the Pearl. When my little ventures into the swamp start feeling arduous and dangerous, all I have to do is think about some of the things that Meg has done, and that puts things in perspective. I would highly recommend her books, "Life in the Treetops" and "It's a Jungle Up There".

2-29-08. Before the talk last night, Meg's students gave a tree climbing demonstration in a spectacular kapok tree, and Bryson Voirin explained why I've been having problems when descending using a Grigri Descender. It turns out that this device sometimes has problems for users over 180 pounds, and I'm about 225 pounds. One solution is to switch to a Stop Descender. Meg and her students are interested in visiting the Pearl and spending some time in the trees watching for ivorybills flying over the canopy. Having such a sighting is by far my most important remaining goal.

3-1-08. Mark Cowart took me for a ride up the Hillsborough River in his motorboat. We were planning to go up to a relatively remote area to search for good habitat. Since the boat seemed to be having a fuel problem, we only made it up to the vicinity of "The High Cypress," but it was nice to go right over to that beloved tree and actually touch it. I took this photo from just beneath, this photo that shows the bend out over the water that made it a great diving platform, and the series of photos in this composite. In 1974, Mark and I free climbed this tree before installing steps. I was pleased to see that the steps have long since rotted away and didn't seem to do any permanent damage to the tree. We also used to jump from this cypress, which had a large branch about halfway up that stuck out over the water. I didn't hear any parulas during my visit to the river a few days ago, but they have now arrived, and the timing is the same as it has been in the Pearl the past two years. The Hillsborough has more of a tropical flavor than the Pearl, but the area that we visited today is surrounded by development. In small patches of good habitat, we saw this Limpkin, a good-sized gator, and many Osprey. During the summer, we usually went swimming in this area, where we would jump out of two towering oaks that fell into the river years ago.

3-2-08. I drove back to the Pearl today. I saw a Swallow-tailed Kite soaring above I-75 in Florida, and they should be arriving in the Pearl soon if they're not here already.

3-3-08. I was worn out after the trip to Florida and didn't make it out in the Pearl, but a visitor (who also spent some time here last year) was my eyes and ears in the field today. He reports unusually high water levels and the arrival of yellow-throated and parula warblers right on time with the past two years.

3-4-08. I will be tied up in the office today. I'm thinking about making a quick run to the Choctawhatchee tomorrow. I've been wanting to take some measurements related to the video that I obtained last year, but the leaves were in the way when I returned last April and extremely high water was a problem when I returned in January. The water is down for now and the leaves are starting to come out. So it's now or never.

3-5-08. I received a Petzl STOP and found that it lets the rope out very smoothly during descents. Since the rope burns are nearly healed, I'm now ready to get back up in the tall cypresses. But first I'm going to make another attempt to take some measurements in the Choctawhatchee where I obtained the video last year. I'll be driving there today and should be back to the Pearl late tomorrow.

3-6-08. I heard a nice double rap early this morning in the Choctawhatchee. It was the second time I've heard a definite double rap, but there's a possibility that the two double raps that I heard in the Pearl on February 5, 2006, were made by a visitor from Cornell. I stopped to keep watch for ten minutes, and there was no sign of anyone else in the area. I had the paddle-cam running, but the double rap was lost in the noise of paddling, which radiates along the paddles directly to the camera. I need to get an external microphone and mount it away from the paddles. I returned to the location where I saw two ivorybills and obtained video on January 19, 2007. In part of the video, one of the birds flew from behind this battered old tree, which is about 120 meters from where I was sitting in the kayak that morning. A little over 20 seconds before the bird flew, it hopped behind the tree in a way that was suggestive of a squirrel. Besides the fact that a squirrel and a large bird wouldn't coexist in the same spot behind that tree for more than 20 seconds, the top of a long-dead tree in a flooded forest is no place for a squirrel. It was a beautiful morning, with early signs of spring. When I got back to the boat ramp, a noticeable amount of new leaves seemed to have popped open during the five hours that I spent in the kayak. I noticed a few cypresses that appear to be favorable observation platforms, but I probably won't have time to return to the Choctawhatchee and give them a try.

3-7-08. I turned 50 today. It was a nice change from last year, when I woke up in the hospital on my birthday.

3-8-08. I gave the new descent device a full test this afternoon. It lets the line out very smoothly. For the next several days, I'll be doing some searching in a different area and may not have Internet access until I get back.

3-9-08. I had to postpone the plans that I mentioned a few days ago due to flooding and strong currents, which made it impossible to get into the area with a kayak loaded with gear.

3-10-08. I just learned that someone was doing double rap simulations near where I heard one during a visit to the Choctawhatchee last week. Both the time and the location are consistent with my observation (although the location is a bit further than I would expect a double rap to carry). It certainly was a good simulation.

3-11-08. It was raining early in the day, and then I got tied up in the office. Better weather is predicted for the next several days, and hopefully the water levels will finally start going down.

3-12-08. I visited the 2006 hot zone this morning. It had been a while since my last trip up there. It was nice to see that Swallow-tailed Kites and other migrants have returned. The water is still high and the currents are still strong. Paddling downstream through fallen trees is really treacherous under these conditions. Although I've been through that area many times, it's hard to know where debris lurks just beneath the surface when the water level changes. Richard Martin sent me another photo of a pileated flying near the fork tree in the Pearl video. Since he was sitting in the spot where I obtained the video, I was able to scale the images and obtain these comparisons. Although the ivorybill (20 inches) isn't that much longer than the pileated (17 inches), the ivorybill is a much more massive bird, and the pileated looks puny by comparison in these images.

3-14-08. I made the rounds on the Mississippi side this morning. The most interesting sighting was a pair of pileateds that appeared to be in the type of long distance flight that would be expected of ivorybills. I saw them coming from far off to the right and tracked them until they nearly vanished to the left, but they eventually veered around back toward their starting point. It wasn't the first time that I've seen such a flight by a pileated in pine forest, where it is conceivable that they would need relatively large territories.

3-16-08. Since I have to return to our Washington office in a few weeks, I'm spending this weekend catching up on things that need to be completed before leaving our Stennis office. I heard a nice double rap in the Choctawhatchee on March 6 and reported it to Geoff Hill. In the same area in January, Geoff heard two double raps and two birders had a sighting. Although Geoff didn't think anyone would have been simulating double raps in that area, Brian Rolek later informed me that his assistant had been simulating double raps at the top of each hour that morning (he thought the location of the simulations might have been within earshot of my position, but he would have to check on it). I didn't see anyone else in the area, but the time of the double rap was nearly on the hour at 7:01 a.m. After checking the records, Brian has determined that I was more than a mile from the simulations. Since the double rap seemed to come from a nearby source, the timing was apparently just a coincidence. Hopefully, the birds are still spending time in that area and the Auburn folks will soon get a photo.

3-17-08. I'm still stuck in the office and might not get out in the field for another day or two. Robert Caputo wrote to suggest that the double rap that I heard in the Choctawhatchee might have been a response to a simulated double rap. I had considered that possibility, but the distance seemed to be too great. Robert's note got me to thinking about it again. Perhaps this would be possible if (a) the ivorybill has keen hearing that allows it to detect distant double raps, (b) an ivorybill was in a position high in the treetops that was favorable for hearing a distant double rap, and (c) the source of the double rap that I heard was further away than it seemed (this would allow the ivorybill to be closer to the simulated double rap).

3-18-08. It was a gorgeous morning in the Honey Island Swamp. Prothonotary Warblers and Yellow-throated Vireos have arrived since my last trip over there. The leaves are really starting to come out, and we're getting into the time of year that I suspect is the most favorable for watching for ivorybills flying over the canopy. I have plans to do some treetop observing this weekend.

3-19-08. It was raining early this morning, and I've been tied up in the office since then. I'll try to get out tomorrow, but I still have a lot of work to finish before returning to Virginia. I was re-reading one of the accounts by Agey and Heinzmann and noticed the following:

"Then on Dec. 17, 1967, the best sight record since the first observation came when an Ivory-bill approached across a wide arm of water, coming in directly overhead at about 40 feet, and spreading its wings to land in a tree overhead. At the last moment, it apparently spotted us, and flew on deep into the woods."

There are similarities between this sighting and the probable sighting that three of us had here in the Pearl on February 16. The bird glided in on fixed wings at about 40 feet and didn't seem to notice us at first. We lost sight of the bird when it landed, but one of the observers saw it swoop down and into the woods. Agey and Heinzmann saw an ivorybill near a roost tree (where they later found an ivorybill feather), but the bird was never again seen near that tree. This suggests that anyone who finds a roost tree had better not blow the opportunity because they might not get a second chance. Agey and Heinzmann also mentioned records of nest trees that were quickly abandoned, which suggests that nesting attempts are doomed to failure in areas where intensive searches are being conducted.

3-20-08. It's a gorgeous morning, but I can't get away from the office. I should have work-related tasks wrapped up soon, and then I'll make a final push out in the field. This morning, I saw two Swallow-tailed Kites flying from the Pearl toward the swamps and pine forest to the east. I've seen them take this route several times. When at Stennis near dawn or dusk, I always watch for an ivorybill making a similar commute.

3-21-08. I was stuck in the office again on another gorgeous spring day. The good news is that I'm getting caught up with work and should have plenty of time to get out in the swamp during the next several days. While walking to lunch, I saw my first Monarch Butterfly of the year.

3-22-08. I'm not going to do any searching this weekend, but I have some tree climbing plans for the coming week. I'm planning to start back to Virginia on March 29. I need to return early this year due to a new project that is starting up.

3-23-08. I decided to take a close look at the bark adhesion analysis in the Choctawhatchee paper. I immediately recognized this as important work when Geoff Hill was kind enough to give me a sneak preview just before the paper came out, but there was a confusing detail, which I now understand. Bark adhesion is quantified in terms of force per unit area, but the measurements were in terms of force. This is merely a matter of semantics. The measurement technique clearly makes sense since it replicates the force that is applied when a woodpecker pries bark from a tree. The approach is based on essentially estimating the point force at a particular location that is required to pull bark away from the tree. This makes sense since the prying bill of a woodpecker can be modeled as a point force, but the quantity that was measured wasn't really bark adhesion (although it is closely related).

3-24-08. I made up for the inactivity over the weekend with one of my most grueling days in the field. Gretchen gave me a one-way boat ride to Tree 5, and I made it to the top right at sunrise. It was my first serious climb since the incident on February 10. It's hard to get back on the horse after being thrown, and I had to do it in less than ideal conditions. Tree 5 is about 90 feet tall, the climb is about 80 feet, it's way out in the middle of the swamp, there are lots of ominous looking dead branches near the top, there were high winds, and I had to do the climb alone. It was an exhilarating climb despite the wind and cold. As this photo shows, the swamp is very beautiful at this early stage of spring, when only about half the leaves are out. Most of the biggest cypresses (including Trees 3 and 5) still don't have their leaves out. The highlight of the climb was a pair of Yellow-throated Warblers that appear to have a nest near the top of Tree 5. These birds showed absolutely no fear of me and approached very closely. After what happened on the last climb, I was most nervous about the descent, but the new Petzl STOP worked very smoothly the whole way down. The climb and the trip back were like a triathlon. After the climb, I had to transport all the gear (including the kayak) several hundred meters through the semi-flooded forest. This was the most exhausting part of the triathlon, but the kayak ride back was the marathon, taking about three hours due to the strong winds (which always seemed to be in my face).

3-25-08. In some ways, I'm starting to feel my 50 years. Dragging a loaded kayak through a flooded forest nearly kills me. If it's flooded the whole way, you can just get in the kayak and paddle, but this doesn't work when there are areas that are dry or shallow or obstructed by fallen vegetation. The factor that makes it so hard to transport a heavy weight through such habitat is that your feet sink in the mud with every step. Just before the end of the drag, I nearly fell in a deep hole and came within inches of getting my waders full of water. I saved myself by grabbing the kayak. One of the things that worries me out in the swamp is getting pulled under by flooded waders. After the drag, I had a long kayak ride back and paddled like a well-oiled machine for three hours, but then the wind started blowing hard in my face. I got to the boat ramp just south of Stennis and was spent. My friends at Stennis, Bob Brown and Steve Stanic, came to the rescue and picked me up. I was staggering out of the kayak with severe cramps in my right thigh as they pulled up. Here is another frame from the video of the Yellow-throated Warbler that shows its feathers being ruffled by the wind. I've always wanted to get a photo like this of a flicker, which shows the brilliant yellow feathers underneath in ideal light, but the quality is poor since I was panning the video camera.

3-26-08. I had a possible sighting this morning not far from the probable sighting last month. I noticed the bird as it flew through the far side of this flooded area. It was a large dark bird with lots of white on the wings, including what appeared at that distance to be a completely white underwing. I spoke to a biologist who has been doing research in the Pearl for several years and who confirmed reports that I had been hearing about logging further north in the Pearl. They have not only logged the area but have made a mess of it with logging roads. It's a disgrace that such things are happening in a river basin that contains a critically endangered species. Indigo Buntings and Hooded Warblers have arrived.

3-27-08. This morning, I began the process of moving out of the house in Waveland and getting my stuff packed up and stored away. I plan to spend some time in the field during the next few days, but then I'll be winging it back to Virginia. I have decided to stay for an extra day and will try to get in two or three more sessions in the cypresses.

3-28-08. I took my final kayak ride of the season and visited the 2006 hot zone. The most interesting experience was a Barred Owl that flew right over and stared down at me. I tried to get it on the paddle-cam but missed. Although the kayak has been put away, I plan to do two more climbs if the weather permits. While in Tree 5 a few days ago, I saw lots of birds flying above the canopy. Based on video footage that I got during that climb, it now seems clear that birds use the tallest cypresses as landmarks to navigate through the Pearl. I noticed birds that seemed to be navigating using Tree 5 and two other tall cypresses that are well within camera range. It sure would be exciting to see an ivorybill flying directly towards me from a distance.

3-29-08. I hiked out to Tree 6 before dawn and spent several hours up there this morning. There were several interesting flybys, including a Wood Duck that flew along the channel below. I got nearly two hours of video but don't have the time right now to inspect it. There's something important about the video that I obtained in Tree 5 that didn't occur to me right away. The motive for searching from trees is to increase the encounter rate. An unobstructed view from the top of a tree makes it possible to identify birds out to distances perhaps ten times greater than from the ground. This means that the area that can be monitored is perhaps one hundred times greater from a tree. What I see in the video seems to be consistent with this estimate. Most of the birds that appear in the video would not have been visible from the ground.

3-30-08. Before packing up my computer for the trip back to Virginia, I took a quick look at the video from Tree 6. The most interesting sighting was a large dark bird that flew along the channel below with a duck-like flight. I assumed it was a Wood Duck and aimed the camera at it rather than the binoculars. Just before it passed directly below, I caught a glimpse of white on the neck or back. The video quality is poor since the camera focused on tree branches in the foreground, but these frames are interesting. The top frame shows the underside of the bird reflected off the water (the bird itself was hidden behind vegetation at that point). The bottom frame (and other frames in that part of the video) appears to show a white trailing edge. The arrows indicate the direction of flight. The flap rate is about ten flaps per second. It could be a Wood Duck, but I'm not familiar with all the nuances of that species when viewed from directly above. If it's an ivorybill, it sure would be ironic to have spent so much time rigging trees and learning to climb in order to keep watch above the canopy and then have one fly right below me.

3-31-08. I made it back to Virginia this afternoon. I miss my friends down south, but it's good to be home. When viewed on a TV, the new video is much more interesting than the individual frames. I'm going to ask several people (including duck hunters) to inspect it. If Wood Duck can be ruled out, I'll try to return to the Pearl within the next few weeks. Someone raised the possibility of the white being due to specularly reflected sunlight, but the bird was nearly directly below and the sun was still low in the sky. While climbing Tree 6, I inspected a massive cavity that was under construction about 25 feet above the ground. I couldn't imagine how a woodpecker managed to do such work on a living cypress. I didn't get a photo because the camera is stowed away in my backpack while climbing.

4-1-08. I'm getting some interesting feedback on the new video. Two duck hunters have studied the still frames. Although one of them thinks it's a Wood Duck based on shape, the other one believes that Wood Duck can be ruled out. Since it was only an hour and a half after sunrise on an overcast morning, I don't see how a Wood Duck could show so much white on the wings. I've produced a DVD that plays the footage repeatedly at various speeds. I showed the DVD to a birder who wasn't sure what to think of the isolated frames. After watching the DVD, he believes that Wood Duck can be ruled out and that it could be an ivorybill. After studying the video, I noticed that the reflection of the bird appeared more prominent than the bird itself after it passed Tree 6. I noticed what appeared to be dorsal stripes just before the bird passed but was confused by what I saw next. The source of the confusion could be that I picked up the reflection rather than the bird itself after it passed. Since something didn't seem to add up, I didn't post anything about the sighting until I had a chance to study the footage, but I did tell two visitors that morning that I saw what appeared to be dorsal stripes.

4-3-08. I mailed the footage from Tree 6 out to several people this morning and look forward to hearing their impressions. If Wood Duck can be ruled out (e.g., by the flap style or the field marks), I will try to return to the Pearl later this month and keep watch from a few trees in that general area, which is near the 2006 hot zone and the locations of the recent probable and possible sightings. Otherwise, I just don't have the time for such a trip right now. In the meantime, I might ask a local birder to check on the cavity that was under construction on Tree 6.

4-4-08. After spending some time observing from trees, I'm starting to get the impression that seeing out to great distances isn't the only advantage to this approach. Birds don't seem to be as wary when I'm in tree and seem to be less likely to even notice me. Several birds have flown past within a few feet and some have landed in the tree with me. A few birds (such as crows, ducks, and herons) have changed course slightly after noticing me.

4-7-08. I have received feedback from a duck hunter who has studied the new video frame by frame on a computer. He believes that the bird in the new video can't be a duck since it flies with a non-duck-like rowing motion. Dalcio Dacol has pointed out that the flight of the bird in the new video appears to be similar to the flights of ivorybills captured in photos by Tanner that are posted here. Several frames from the new video and images from the Tanner photos are compared here. The images in the left column are of the bird as it approached the tree. The first two images in the right column are of the reflection of the bird off the water just before the bird passed beneath the tree. The other two images in the right column are from the Tanner photos. Unlike the flight of a duck, the wings are brought in close to the body in the new video and in the Tanner photos. There is a similarity in the wing position in the second and fourth images in the right column. Wing bowing (which appears in other known and putative images of ivorybills) appears in the first and fourth images in the left column. The bird flew with about ten flaps per second and showed lots of white on the trailing edges of the wings. Although it passed beneath the tree very rapidly, I saw what appeared to be dorsal stripes. I will await input from others, but I'm starting to think seriously about returning to the Pearl to stake out this area for a week or so. This seems very promising since Tree 6 is only about 400 meters from the 2006 hot zone, and the probable sighting on February 16 was only a short distance up the same waterway.

4-8-08. It has occurred to me that the bird in the new video was flying up the channel from the area where I found extensive foraging sign on January 17. It's highly fortuitous that the bird and its reflection off the water are both visible in much of the new video. The flap style is well resolved in a series of reflected images. The wings appear to be fully extended and very long in a few of these images. The image of the bird itself also shows interesting aspects of the flap style, but the most important part of this component of the video is the appearance of the white trailing edges, which persist through many frames. There seems to be something amiss about the historical accounts of a duck-like flight by ivorybills. What I understand to be duck-like flaps doesn't involve nearly closing the wings during each flap as in the second image in the left column above (from the video) and in the third image in the right column (from a Tanner photo). I have never noticed this type of rowing motion in the flight of a duck. It's possible that ducks have such flaps, and I just never noticed it since the flaps are so rapid. Since nobody ever had the opportunity to study the details of the flaps of a cruising ivorybill in slow motion, it's also possible that the cruising flight wasn't fully understood. In the first and fourth frames, the action seems to be concentrated in the outer parts of the wings as described by Eckleberry in 1944, but it's clear from the second image in the left column that there are also significant movements of the inner parts of the wings during part of the flap cycle. This clip (which is sampled at 60 frames per second and plays at half speed) shows the rowing flap style. The flap rate in this part of the video is about 8.5 flaps per second. The underside of the bird, which is visible as a reflection off the water, appears very dark just like the reflections of trees in this image from the video. A leading duck hunter in Louisiana has viewed the rowing flap style of the bird in the new video and agrees that it's not a Wood Duck. He initially thought that Wood Duck might be a possibility based on the frames that I posted on March 30, but it's hard to make such a judgment based on isolated frames. I'm now convinced that the bird in the video must be an ivorybill. What other possibility is there with such a high flap rate, an unusual (but consistent with Tanner photos) flap style, and white trailing edges? I should have trusted my eyes when I saw the dorsal stripes, but it's hard to be certain about something that happens so fast. When the raw video is viewed at full speed, it's amazing how fast the bird flies past the base of Tree 6.

4-9-08. Last year, a birder told me about two high-quality sightings that he had many years ago. His description of the flight style as a "straight purposeful rowing" is spot-on with what appears in the new video.

"During my first sighting the male, after landing and hitching on the trunk giving me both a perfect profile and back look, flushed once it saw me with a rustling burst and straightlined it out of there. My second sighting was from a bridge near the border of Georgia and South Carolina towards the end of the day. A pair was flying across the waterway one slightly staggered behind the other. I got a good look from a distance looking downward so I could see the trailing edges and dorsals quite clearly. They didn't seem to be going all out but they weren't slow either, more of a straight purposeful rowing. I probably saw them for 3-5 seconds as they made for the opposite treeline. I understand why people say ducklike flight to differentiate from the undulating flight of the pileated, but I also think it is something of a misnomer as it is somewhat different."

An exciting aspect of the new video is that there are points of reference (such as tree branches) that should make it possible to return to the scene and determine the flight speed. This quantity has never been measured since nobody has had footage of an ivorybill in cruising flight until now.

4-10-08. These images show the white trailing edges through three frames that are spaced by 1/60 of a second. After the trip back to the Pearl, I'll have some analysis to finish up on the new video. I'll try to get the measurements that are required for computing the speed of the bird. I will also get better estimates of the flap rate, which varies throughout the flight (it appears to be just under 7 Hz at one point).

4-11-08. I've come down with a bad cough but will try to get on the road to Louisiana this evening. Here are some images from the March 29 video that show the views down the bayou, nearly directly below, and up the bayou.

4-12-08. I didn't get started on the trip until this morning but made it well into Alabama. I had some interesting discussions about the new video during the drive. A question was raised about Tanner's photos of ivorybills in flight: How do we know the type of flight that is shown in those photos? In one of the photos, it seems clear that it's a high-speed flight (like the bird in the video) since the wings are swept back. A few people have asked why the bird doesn't show more black. During the approach from a distance, the bird appears small, presents a nearly edge-on cross section, and is coming from a direction of relatively high glare (despite the overcast conditions). One wouldn't expect to see much detail under such conditions. As the bird neared the tree, it disappeared beneath vegetation (but its reflection remained in view). After the bird passed the tree, the light conditions were more subdued and black markings could have been lost in the dark mud in the background. It should be possible to estimate the aspect ratio of the white trailing edge feature and the aspect ratio of the full wing from the reflection off the water. If these objects have different aspect ratios, this would suggest that black features were indeed lost in the background. The new video has been shown to some of the most experienced duck hunting guides in Louisiana. The consensus among them is that the bird is not a duck.

4-13-08. I have arrived back in the Pearl. It's always nice to let people discover things for themselves. I showed the new video to a local birder, who noticed that the flap style isn't duck like but is actually similar to the flap style of a pileated (but with a much higher flap rate and without the pauses with tucked wings).

4-14-08. I returned to Tree 6 and determined that the bird in the video flew approximately 81 meters in 5.5 seconds. This corresponds to a speed of about 33 mph, which is much slower than I would have guessed. I obtained this value from the ground. I plan to obtain a better estimate by taking images from the video up the tree.

4-15-08. Sitting at a stakeout isn't my preferred approach for searching, especially while sick on a chilly and damp morning. Since the cough got worse, I spent the afternoon in bed.

4-16-08. I spent the morning at the stakeout. I found a place where I'm well hidden, the view down the channel is good, and I can sit comfortably for several hours.

4-17-08. Just after sunrise, I recorded these loud raps near the site where the video was obtained on March 29. They sounded very powerful and wooden and didn't seem to be gunshots. They were reminiscent of the loud raps that I heard in the fall of 2006. This image shows the view looking down the channel from which the bird came on March 29. This image shows the dark mud over which the bird flew on March 29. The dark leading edges of the wings would have been difficult to resolve against this background. A visitor had two possible sightings not far from the area of the recent activity. These sightings were more than an hour after I recorded the loud raps. The first sighting was a large dark bird with lots of white on the dorsal surfaces of the wings that flushed from the same location where I had a possible sighting on March 26 (this location was not known to the visitor). The second sighting was a bird with similar characteristics that flew very fast across an opening.

4-18-08. I spent another morning at the stakeout. There was no sign of The Bird, but there were a few Wood Duck flybys along the channel. I didn't get an exact timing, but they seemed to cover the 81 meters between the two reference points in the March 29 video in less than 5.5 seconds (see April 14 comments), and the flaps weren't at all like those of the bird in the March 29 video.

4-19-08. I spent another morning at the stakeout. It has been interesting to see the different birds that show up there everyday. There were lots of herons the first few days. This morning, I saw a pileated in that area for the first time. It seems likely that the ivorybill will pass through there again, but I'm running out of time. I'm planning to climb Tree 6 in order to get some measurements tomorrow.

4-20-08. A visitor hiked to the stakeout with me in order to help take measurements. Since the area is now flooded, it wasn't possible to get the reference object in position without a kayak, but we did find lots of unusual woodpecker work on Tree 6 and other living cypresses, including these examples. There are also several large cavities in the area. My allergies were bad, but it was a bayoutiful day.

4-21-08. After spending one last morning at the stakeout, I drove nearly halfway home this afternoon and evening.

4-23-08. On the 1042 mile drive back to Virginia, the Honda used only 26 gallons of gas (40.1 mpg). Fred Virrazzi brought the following quote from Bent to my attention: "...it is remarkable how duck-like the bird can appear as it flies swiftly and directly up a lagoon, so much so in fact that certain Louisiana hunters have told me that they have even shot at them under such circumstances, mistaking them for ducks." When I first spotted the bird flying up the channel on March 29, I immediately thought it was a Wood Duck. I might have turned away and ignored it, but fortunately I decided to get some video since I thought it would be an interesting shot from above. It was also fortunate that I happened to be looking in the right direction and spotted the bird far up the channel, which made it possible to capture lots of flaps from different angles.

4-25-08. Based on the flight speed of the bird in the March 29 video, it only takes two minutes for an ivorybill to fly a mile. Due to all the fallen trees, thick vegetation, and muddy sloughs in the Pearl, it can easily take five hours for a two-way "death march" over such a distance. This gives an idea of the advantage these birds have over a hapless human trying to find them.

4-26-08. Although Noel Synder has a fixation on an oddly plumaged pileated that momentarily fooled him and seems to dismiss every ivorybill report as a similar mistake, he has written an important paper on "An alternative hypothesis for the cause of the Ivory-billed Woodpecker's decline." I was pleased to find a copy of this paper in the pile of mail that accumulated while I was in the Pearl. It exposes Tanner's work for what it was--an extremely limited and flawed study by a graduate student.

4-27-08. A well known ivorybill searcher told me about a sighting in which he estimated the flight speed to be 30 to 35 mph, which is in good agreement with the 33 mph estimate that I obtained from the March 29 video. This observer used to practice estimating flight speeds while driving through a refuge on the way to work every day and got to the point that he was usually within 5 mph.

4-30-08. The account of the ivorybill in Bent's "Life Histories of North American Woodpeckers" contains the following comment by Audubon:

"The transit from one tree to another, even should the distance be as much as a hundred yards, is performed by a single sweep, and the bird appears as if merely swinging from the top of the one tree to that of the other, forming an elegantly curved line."

It was exciting to observe this behavior in Florida last year. When I first came upon a pair of ivorybills, they repeatedly swooped between perches in the canopy. I obtained video clips of three of the swoops, and the longest of these traces out an elegantly curved line.

5-1-08. A leading expert on the flight mechanics of birds is analyzing the March 29 video. He is "confident that it is a large woodpecker" and that the flap rate is "much too high (well outside three standard deviations) to be from a PIWO." These comments alone lead to an obvious conclusion, but the expert also noted "considerable white (or light gray) visible on the upper surface of the wings" and mentioned that "those patches of light-colored feathers would seem to be consistent with an IBWO." The expert also noticed "pauses in mid-upstroke during which the bird holds its wings flexed in a bound posture." This wing-tucking behavior is well known in other woodpeckers but had never been reported for IBWO. The expert pointed out that "observers of a live bird in the field (e.g. Tanner) would likely miss" this aspect of ivorybill flight since the flaps are so rapid and the tucking is much briefer than in other species.

5-4-08. I located the tape that contains the Choctawhatchee video that I obtained on January 19, 2007. I downloaded the first eight minutes of that tape upon getting back to Stennis after the Florida visit. It wasn't until April 23, 2007, that I discovered that the camera picked up clips of the birds that I saw swooping around in the canopy. By then, I wasn't sure of the location of that tape. This weekend, I went through some old tapes and found it. When I arrived on the scene that morning, I saw two large birds swooping around in the distant canopy in classic ivorybill form. This brought to mind Audubon's observation that "the flight of this bird is graceful in the extreme." I decided to rewind the tape since it seemed that the encounter would be extended. This took about two minutes and might have caused me to miss out on some interesting footage. Rewinding seemed to be a better alternative than digging for another tape, which would have required taking my eyes off the birds. One of the birds flew from behind a tree at 5:37 (min:sec) into the tape. Three deer ran through the area at 7:45. By 12:00, it seemed that the birds had left the area. I got out of the kayak for several minutes but left the camera aimed in the direction where the birds were last seen. At 15:23, the camera picked up this upward swoop. This clip plays at half speed and was obtained a little to the north of the position where I was sitting in the kayak. After moving to the new position, glare from sun was no longer an issue, and lots of white is resolved on the underwings. It's amazing how rapidly the bird swoops nearly vertically upward. This swoop is similar to (but better resolved than) the other upward swoop that was obtained that morning. At 16:20, another birder arrived at the scene. I left the camera in place while telling him about the sighting with a combination of hand signals and whispers (part of this dialogue was picked up by the camera, but I can't make it out). After being separated from the other birder for a few minutes, I urged him to radio the other searchers, who had fanned out around the area after a sighting the previous day, and let them know about my sighting. As a temporary visitor, I was the only one at the Bruce Creek camp who didn't have one of the radios, which were designed to simultaneously inform everyone of sightings and to automatically relay GPS coordinates. I described the sighting to the other birder, mentioning the swooping behavior and the white trailing edge, and he radioed this information to the other searchers before I left the scene.

5-6-08. The ivorybill has a fascinating flight repertoire. I have observed dramatic swoops, takeoffs with deep and rapid flaps, high-speed glides on fixed wings, and high-speed flight with rapid flaps. Due to the rapid flaps, it would be easy to miss certain details. In fact, a woodpecker expert has noticed details in the March 29 video that he believes an observer such as Tanner would not have been able to detect during an observation of a live bird. In the paper that announced the Choctawhatchee findings, the section on human detections mentions sightings of ivorybills that were flying with "stiff wingbeats." Although this report is consistent with Don Eckleberry's description of ivorybill flaps (based on his observations in 1944), it isn't consistent with the flap style of the bird in the March 29 video, which the woodpecker expert has identified as a large woodpecker that is not a pileated. It's possible that observers who have reported duck-like flaps were influenced by reports of a duck-like flight in the historical literature. Since those reports caused me to expect duck-like flaps, I was confused by the flap style in the March 29 video until Dalcio Dacol pointed out Tanner photos that show flaps that are clearly not duck-like. I have received interesting news from a participant in one of the official searches. In 2006, one of the searchers had a sighting and described a flap style that is consistent with the bird in the March 29 video. Although the observer got it right, his report was met with skepticism by the other members of the search team since his description of the flaps was not duck-like. The historical reports of a duck-like flight were apparently based on the speed and directness of the flight rather than the flap style.

5-9-08. For more than a year, my goals had been to see the dorsal stripes (which I had always missed by locking onto the brilliant white patches on the wings), see an ivorybill in cruising flight (I couldn't quite imagine a woodpecker flying like a duck), and have a sighting from the top of a tree (I thought about this long before my first climb). I was incredibly fortunate to fulfill all of these objectives on March 29. The view of the dorsal stripes was a brief flash, but I saw them both. I saw the cruising flight and initially mistook the bird for a duck, but it turned out that the flaps aren't duck like at all. I saw an ivorybill from more than 70 feet up in a cypress, but I was anticipating seeing one flying over the treetops in the distance and never imagined that one might fly directly below (this was an example of truth being stranger than fiction). I would still like to see an ivorybill cruising over the treetops and get a better look at the dorsal stripes. It would also be incredible to see the bill and the underwings, have an extended observation, watch an ivorybill foraging, and hear an unquestionable double rap (coupled with a sighting to eliminate any doubt). I would also like to see ivorybills in other locations, such as South Carolina. These new objectives will motivate me to keep going with the search.

5-10-08. After performing a detailed analysis on the March 29 video, the expert is still confident that the bird is a large woodpecker and that the flap rate is much too high for pileated. An object of known size that appears in part of the video provided a convenient length scale, which I used to confirm that the bird has the wingspan of a large woodpecker (on the order of 30 inches). This is consistent with my impression that it was a large bird from the time I spotted it far up the channel until it passed below Tree 6.

5-12-08. When the tree climbing experts visited the Pearl last year, I decided to video tape them rigging one of the trees and just happened to select Tree 6. It was a fortunate choice since that's the tree from which the March 29 video was obtained. Jerome Jackson recently complained about "millions of dollars of public money that's been spent based on no really good scientific evidence." If Jackson is really interested in science, then he should explain why a video that shows a large woodpecker with a flap rate that is much too high to be a pileated (according to a woodpecker expert), a fast and direct flight, and large patches of white on the dorsal surfaces of the wings isn't good scientific evidence.

5-13-08. A paper by Tobalske (Auk, 1996) lists the range of the flight speed of the pileated to be 7.5 to 11.6 m/s. The large woodpecker in the March 29 video has a flight speed of about 14.7 m/s. These numbers are consistent with my impression that the bird was flying much too fast to be a pileated when it shot past Tree 6.

5-14-08. Louis Bevier has presented an analysis of wingbeats that is based on the assumption that flap rate depends only on body mass. In contrast to this hypothesis, flap rate would actually be expected to increase with mass if everything else were held fixed (e.g., consider a raptor taking off with large prey). Flap rate actually depends on many factors, such as wing surface area (e.g., consider a bird struggling to fly with damaged or missing feathers). The ivorybill has a similar body shape and wingspan as the pileated, but it has a smaller wing surface area and is perhaps twice as massive as the relatively small pileateds within its range. Based on this reasoning, it makes sense that the videos that I have obtained of two takeoffs into level flight and a short flight show deep and rapid flaps that are dramatically different from pileated flaps under similar conditions. I have obtained the first footage of an ivorybill in cruising flight, and the flap rate ranges between 6.6 and 7.5 Hz. The flap rate of the pileated is 3.7 +/- 0.4 Hz according to Tobalske (Auk, 1996). Cornell performed a similar study in Arkansas and obtained similar results. It should be noted that there are two factors associated with flap rate that could potentially cause confusion: (1) There are two definitions in use for flap rate. Since woodpeckers have a habit of holding their wings fixed during pauses, Tobalske used a flap rate that is defined by subtracting out the intervals in which the wings are held fixed (Auk, 1996). The reduced flap rate, which in general is lower than the flap rate used by Tobalske, is defined to be simply the number of flaps divided by the elapsed time. The reduced flap rate is more objective since it doesn't require decisions on when the flapping and resting phases begin and end. The flap rates presented on Bevier's web page are from Tobalske's paper. The reduced flap rates are much lower (e.g., 3.7 +/- 0.4 Hz for pileated). Either definition of flap rate could be used as a characteristic for identification. Since the flap rate is high and the pauses only last for a few frames in the 2008 Pearl video, flap rate calculations are very sensitive to errors in the estimates of when the pauses begin and end. For this reason, it makes more sense to use the reduced flap rate with this data. The unusually brief nature of the pauses in the 2008 Pearl video is another aspect of the flight of that bird that is inconsistent with pileated. In that video, the flap rate appears to exceed 8.5 Hz (and perhaps even 10 Hz) when the pauses are removed. (2) The bird in the Arkansas video was gaining altitude during an escape flight. It is difficult to use flap rate as a discriminant under such conditions since flap rate may increase well beyond the normal range when a bird is gaining altitude and accelerating rapidly. I have obtained footage of distant birds taking off into level flights and a bird in level cruising flight that didn't seem to notice me in the top of the tree. Neither Tobalske's study nor a study that was conducted during the ivorybill search in Arkansas recorded a flap rate of a pileated in level flight that is comparable to the flap rates of level flights that I have captured on video.

5-17-08. There has been another ivorybill report in the eastern part of the Stennis buffer zone. While following up on one of these reports in 2006, Susan Epps and I saw an ivorybill fly across Texas Flat Rd. There have been three sightings north of Catahoula Creek, one sighting at Texas Flat Rd., and two sightings near I-10. This area is one of the most isolated parts of the Stennis buffer zone and has a mixture of pine forest, swamps, and small waterways.

5-21-08. I received a note from Fred Virrazzi, who has examined footage of many Black-bellied Whistling Ducks and found that they have a duck-like flap style, which rules out this possibility for the bird in the March 29 video.

5-22-08. At an applied mathematics conference this week, I gave a talk on "Physics of an Avian Controversy" in a session on mathematical biology and presented the expert's comments on the March 29 video. In such a setting, it wouldn't have been appropriate to mention comments from an anonymous expert, but Bret Tobalske gave me permission to disclose the fact that he has analyzed the data. Bret seems to be universally recognized as THE expert on woodpecker flight mechanics. Bret's work is always mentioned when this topic comes up, and two biologists advised me to send the March 29 video to him. It has been clear for a long time that the ivorybill controversy has nothing to do with science. If it were about science, the controversy would have been over a long time ago and would certainly end when an independent authority like Bret declares that he's confident that a video shows a large woodpecker with a flap rate that is much too high for a pileated. On May 14, I mentioned a reduced flap rate of 3.7 +/- 0.4 Hz for pileateds in level flight. This value comes directly from Tobalske and is consistent with a study that Cornell conducted in Arkansas. The reduced flap rate of the bird in the March 29 video ranges between about 6.6 and 7.5 Hz.

5-23-08. I started visiting Wakefield Park every morning during spring migration in 1998. This park is located near where I live in northern Virginia and has the type of bottomland forest that I enjoy searching for Oporornis warblers (this type of birding is somewhat similar to searching for ivorybills). It was exactly ten years ago that I found my first Mourning Warbler at Wakefield, and I celebrated this anniversary by finding one there this morning.

5-24-08. Fred Virrazzi brought an interesting article on flap rate to my attention. This article discusses the best performing empirical predictive equation (2.4), which predicts that flap rate increases directly with body mass and inversely with wing surface area. This relationship between flap rate, body mass, and wing surface area is consistent with my intuition and experiences of observing birds carrying heavy loads and birds with missing or damaged feathers (see the May 14 update). In particular, the equation predicts that the ivorybill has a much higher flap rate than the pileated.

5-25-08. In the May 14 update, I discussed two potential causes of confusion regarding flap rates. There's an additional potential cause of confusion that can be understood in terms of equation 2.4 in the paper by Nudds et al. that I mentioned yesterday. The variables in that equation include the wingspan b, the body mass m, and the wing surface area S. If size differences were simply due to the scaling of all body parts by the same factor, then m would be proportional to b³, S would be proportional to b², and it would follow from equation 2.4 that flap rate is proportional to b^-1/2 or m^-1/6. The fact that this one-parameter model is not applicable to birds can easily be seen by considering the ivorybill and the pileated. Despite the fact that the value of b is similar for these species, m is significantly greater for the ivorybill, S is signficantly greater for the pileated, and the prediction of equation 2.4 that the ivorybill has a greater flap rate is consistent with data.

5-27-08. Fred Virrazzi brought an important point to my attention. Animals tend to have longer limbs (Allen's Rule) and lower body mass (Bergmann's Rule) in warmer climates. I'm not sure how these factors apply to pileateds, but they would both favor a relatively low flap rate for this species in the southern part of its range. There is a need for a study involving a large number of samples of pileated flap rate within the range of the ivorybill.

5-30-08. Dalcio Dacol let me borrow his copy of "An Identification Guide to the Woodpeckers of the World," by Winkler et al. For pileateds, wing length is listed as 220-253 mm for subspecies abieticola (northern and western part of range) and 214-235 mm for subspecies pileatus (southern part of range). So Allen's Rule does not apply to this species. I used the mean values for body weight and wing length from Winkler et al., estimated the wing surface area using values posted by Cornell for the wing aspect ratio (1.65 mean for pileated and 2.4 for ivorybill), used Tobalske's value of 5.2 Hz for the pileated flap rate, and obtained an estimate of 6.5 Hz for the ivorybill flap rate. Although this value is slightly lower than the flap rates of the birds in the videos, an empirical formula is not to be expected to produce exact results, and there are uncertainties and ranges in the parameters. Since Tobalske's data is based on abieticola, I used the values for that subspecies to obtain the estimate.

5-31-08. Dave from Michigan has applied some clever analysis and detective work to estimate the flight speed of the bird in the March 29 video. I sent him the raw data and the height of the camera above the water. From a photo that I posted from Tree 6 last year, Dave extracted information about the focal length of the camera, which he then used to estimate angles in the video. Dave came up with an estimate of 31.1 mph that is based on 1.65 seconds of footage during the approach. This is a little below my estimate of 33 mph that is based on 5.5 seconds of footage and approximate measurements from the ground, but the bird was climbing slightly during the approach (apparently to avoid a fallen tree). If I can get help on the ground during the next visit to the Pearl, I should be able to get precise values for the flight speed at multiple points.

6-1-08. I used a map to obtain a rough estimate of the distance between Tree 6 and the 2006 hot zone. It turns out that the estimate was off by 200 meters. The source of the error is that the map is no longer reliable for some of the small waterways. In particular, Tree 6 isn't even close to a waterway according to the map. It turns out that Tree 6 is 600 meters from the 2006 hot zone, 840 meters from the tree in which the bird appears perched in the 2006 video, and 300 meters from the area where I found extensive foraging sign earlier this year (the bird in the 2008 video was flying from that direction).

6-3-08. I've been studying a paper by Pennycuick [Journal of Experimental Biology, v. 199, p. 1613 (1996)], which presents an empirical flap rate model that is based on data for 47 species. An important issue for species identification is how far the flap rate can deviate from the mean of the distribution. According to Pennycuick, "mass and wing morphology, together with some environmental variables such as gravity and air density, define a 'natural' frequency, from which the bird cannot stray too far, in the same way that a pendulum has a natural frequency and can only be driven at frequencies close to this." Detailed results are presented for 15 species in Table 2 of the paper, including standard deviations ranging between 0.10 and 0.64 Hz. It's good to cross-check the findings of different studies, and Tobalske's standard deviation of 0.40 Hz for the pileated fits in nicely with Pennycuick's findings. Another result that is consistent with Pennycuick's findings is the 6.5 Hz prediction for the flap rate of the ivorybill versus the observed flap rate of 6.6 to 7.5 Hz in the March 29 video. When this data point is added to Fig. 2 of the paper, it looks right at home among the other 47 data points.

6-4-08. I noticed something interesting while studying the last few flaps in the video clip that shows a takeoff into level flight in the 2006 video. The takeoff involves deep flaps, with the wings being raised high above the plane of the body. As the bird accelerates to cruising speed, there appears to be a transition into the flap style of the bird in the 2008 video. Parts of the flight are hidden by vegetation, but the last flap shows up fairly clearly. While doing a literature search, I stumbled upon this memoriam of Richard Pough, who conducted an independent study in the Singer Tract and questioned many of Tanner's claims. I was pleased to learn that this great conservationist was an MIT graduate.

6-5-08. I believe in presenting new results when they're hot off the press, but it would have been nice to have asked the following survey question before releasing the March 29 video: "Does the ivorybill have flaps like a duck or a woodpecker in cruising flight?" Based on historical accounts of a duck-like flight, my response would have been duck-like flaps. Over the past three years, everyone I spoke with and everything I read indicated that most people would have given the same response.

6-8-08. Nudds et al. have developed a physics based model for flap rate that depends on flight speed, stroke amplitude, and Strouhal number. Since the pileated and the ivorybill have similar wingspans and the same flap style, the stroke amplitude should be about the same for these species. Nudds et al. derived empirical estimates of the Strouhal number of 0.21 for direct fliers (such as the ivorybill) and 0.25 for intermittent fliers (such as the pileated). The flight speed of the bird in the March 29 video is about 14.7 m/s. According to Tobalske, the pileated has a mean flight speed of 9.9 m/s and a mean flap rate of 5.2 Hz. I obtained an estimate of 6.5 Hz for the flap rate of the ivorybill by substituting into equation (1.1) of Nudds et al. for both species and taking the ratio. On May 30, I applied Pennycuick's empirical model and also obtained an estimate of 6.5 Hz for the flap rate of the ivorybill. It's interesting that two models based on totally different sets of inputs provide predictions that are in line with the flap rate of the bird in the March 29 video.

6-9-08. I'm continuing to digest the paper by Nudds et al. Their starting point is equation (1.1), which can't be applied directly to the March 29 video with numbers that are currently available. It should be possible to estimate the stroke amplitude from the video; since this has not yet been done, I obtained the estimate discussed yesterday by taking a ratio of the pileated and ivorybill predictions. The inputs to equation (2.3) are the Strouhal number, flight speed, and wingspan. I obtained a mean value of 0.775 meters for the wingspan here. When the 14.7 m/s flight speed of the bird in the March 29 video and 0.21 for the Strouhal number are substituted into equation (2.3), the flap rate prediction is 6.8 Hz, which is in good agreement with the 6.6 to 7.5 Hz flap rate of the bird in the video.

6-11-08. A little over a minute before the flyunder on March 29, the video camera recorded the rapping sound in this audio clip. It takes good speakers to hear it, but there seem to be two closely spaced raps.

6-14-08. I have returned to the Pearl for a brief visit. As of the first gas stop during the drive from Virginia, the non-hybrid Honda was getting 42.8 mpg (424 miles on 9.91 gallons).

6-15-08. After dragging a pirogue loaded with climbing gear more than a mile to Tree 6, I barely had enough energy left for the climb. Using images from the video, I guided Gretchen and Susan to various positions on the water, where they drove marker stakes into the mud. It turns out that the flight speed (which we measured over two segments) is a little greater than the crude estimate that I obtained from the ground in April. This will push the Strouhal prediction for the flap rate a little higher. We used the laser rangefinder to determine that the camera was about 80 feet above the water; we double checked this measurement using a line loaded with a lead weight.

6-16-08. Susan took this photo of me climbing Tree 6 yesterday.

6-17-08. Two visitors joined me for some exploring in the general area of the recent sightings. Before the visitors arrived, I came upon at least twenty Swallow-tailed Kites, including this group. Later on, we encountered other cooperative subjects, such as this Mississippi Kite and this rabbit.

6-18-08. Dave from Michigan and Mac from Alabama joined me for a visit to Tree 6, where we took some additional measurements (including another check on the camera height with a tape measure). To estimate the wingspan of the bird in the March 29 video, we took photos of scaled reference objects at positions corresponding to the approach and when the bird was nearly directly below. For each case, the wingspan appears to be about 30 inches. While up top, I got a photo of a Mississippi Kite that flew by at close range. On the way down, I got a photo of this unfinished cavity (there are several others like it in the area).

6-20-08. I had a possible sighting early this morning. It was to the north of the most recent sightings. The size, flap rate, and amount of white appeared to be right. I spotted the bird flying slightly below the canopy just before it disappeared behind the crown of a large oak. Dave from Michigan joined me on a long hike, and we saw a velvet ant, which is actually a wingless wasp with a potent sting.

6-21-08. Dave from Michigan heard kent-like calls while investigating a commotion involving agitated pileateds. Like the possible sighting yesterday, this was to the north of the recent sightings. I spent the morning down near Tree 6. I saw two adult Swallow-tailed Kites dive bomb a juvenile. One of them swooped so aggressively that there was a loud sound from the wings. On the way out, I saw a huge wild hog and heard a Swainson's Warbler singing.

6-22-08. While at Tree 6 yesterday, I took photos looking downstream and upstream. Tree 6 is the cypress with a low branch extending out over the water. Two stakes that mark positions of the bird are visible in the upstream photo.

6-23-08. It was a beautiful morning in the swamp. On the way in, I flushed a turkey less than ten feet away. It was quite impressive to see and hear it explode into flight. On the way out, I saw a bobcat. I had previously seen jaguar and mountain lion tracks, but this was my first sighting of a cat in the wild. It was in an area with a large population of rabbits. There have been suggestions that the bird in the March 29 video is a kingfisher. Besides the fact that the large white patches on the dorsal surfaces of the wings are inconsistent with kingfisher, the wingspan is way off. As can be seen from photos of reference objects that are now posted here, it is clear that the wingspan of the bird in the March 29 video is significantly greater than the 24-inch wingspan of the kingfisher.

6-24-08. Mark from New York is in for a visit. I showed him around the 2006 and 2008 hot zones. We covered about eight miles on foot and four miles on the water. It was my first time in the kayak since the end of March. Mark found some interesting foraging sign near where I had my first sighting in 2006. I found what appear to be bobcat tracks far from the location of the sighting yesterday. There has been a lot of pileated drumming the past few days.

6-25-08. Mark and I covered a lot of ground again this morning. We did some exploring on a trail that I had never tried and found that the habitat is degraded. We tried to do some exploring in another area, but the vegetation was too thick. During the hike yesterday, I obtained photos of this buttonbush and this paw print.

6-26-08. It was a nice morning out in the swamp. Since my legs were a little sore from the recent hiking, I decided to do a stakeout at Tree 6, where I saw this butterfly, which Jonny Kemp identified as a female Spicebush Swallowtail. Lots of rotten wood has been falling recently. On the way to Tree 6, a medium-sized tree came crashing down just up the trail. This recent fall contains an old cavity.

6-27-08. It was a grueling day in the Pearl. This morning, I did a stakeout at Tree 6. This afternoon, Gretchen and I waded nearly a kilometer into the swamp to Tree 0. There are so many big trees in that grove that it took a while to find the right one after we had navigated to within 100 meters. Since the previous visit on February 10, vines grew about 25 feet up both sides of the rigging line. Gretchen climbed to the top, while I took it easy down below. In this panorama of Tree 0, Gretchen is barely visible about 100 feet up. Although the view was limited by the surrounding trees, I got the laser on one of the branches near the top, and it was over 100 feet. We encountered several snakes on the way back.

6-28-08. I had another possible sighting this morning in the same area as the previous one. Possible sightings are maddening since they leave you with the feeling that another opportunity may have gotten away. I usually don't spend much time following up on possible sightings unless they are nearly certain (e.g., the sighting on February 16 this year). I won't have a chance to follow up on this one since the time has come to return to Virginia. It was a successful visit since I was able to pin down the wingspan and flight speed of the bird in the March 29 video. I thank Susan, Gretchen, and Dave for the help in taking those measurements. It was also nice to have Mac and Mark in for visits during this trip to the Pearl.

6-29-08. I have arrived back home in Virginia. The Honda got 41.5 mpg despite several major traffic jams.

7-1-08. During my recent visit to the Pearl, yet another biased article was published on the ivorybill. Since the author mentioned my work but didn't bother to contact me, it was obviously a smear job. The author claims that I see ivorybills regularly in Louisiana. I have had a dozen or so sightings during 81 weeks of fieldwork. Many of these came during a cluster of activity in February 2006, and there were long dry spells, such as the gap between sightings on October 21, 2006, and February 16, 2008. This doesn't fit my definition of regular sightings. I do have more sightings than most other searchers and have obtained more video footage than anyone else, but this isn't the first endeavor in which I have had more success than my peers. The author points out that I mentioned a Wood Duck flyby in my March 29 update. As a matter of fact, at least two Wood Ducks flew by that morning (it's possible that I missed others while keeping watch over the treetops). My goals that day (which was my last in the field) were to squeeze in one last observation session from Tree 6 and then to finish preparing for the trip back to Virginia. Lugging climbing gear to a remote location and then climbing up to about 75 feet is exhausting work on a hot and humid morning. After the climb, I didn't have the time or energy to download and examine the nearly two hours of footage that I obtained from Tree 6. Since I had not yet examined the video, I didn't mention anything about seeing a bird with dorsal stripes in the March 29 update, but I did tell Susan Epps about it when we met in the field shortly after the climb. I assumed that the bird was a Wood Duck when I first spotted it coming up the channel, and that was a natural assumption for a fast-flying bird with a duck-like flight in a Louisiana swamp. I kept the camera on the bird until it was nearly directly below, when I moved my eye from the viewfinder while passing the camera to the other side of the climbing rope (as can be seen in the video). It was at that point that I saw the dorsal stripes. After taking a quick look at the video before starting back to Virginia on March 30, I posted a few frames that show extensive white on the dorsal surfaces of the wings, but I didn't make any conclusions since the flap style didn't seem right for ivorybill. As a matter of fact, the flap style didn't seem right for Wood Duck either, but that was the only conceivable alternative in terms of size, flight speed, and white on the wings. I didn't conclude that the bird in the March 29 video is an ivorybill until more than a week later, when Dalcio Dacol resolved the apparent flap style paradox. What the author refers to as "a series of mathematic contortions" are in fact comparisons with the two leading models for flap rate (which were published in prominent scientific journals) and straightforward measurements at the site to determine the flight speed and wingspan (which are useful for identification). These quantities are well resolved in the video, fit the models and what is known about the ivorybill, but are not consistent with any other species (e.g., the wingspan is inconsistent with kingfisher and the flap rate and flight speed are inconsistent with pileated). The author makes accusations of innuendo and misinformation, but he is the one who is guilty of such tactics.

7-2-08. I occasionally get questions from birders who don't comprehend the difficulties of obtaining images of the ivorybill and doing fieldwork in swamp habitats. For example, I was recently asked why I didn't zoom the camera in the latest video. Based on the refined measurements that I recently obtained, the bird streaked by the base of the tree at more than 35 mph. I didn't notice the dorsal stripes until the bird was nearly directly below. Even if I had reacted instantly to seeing the dorsal stripes, I only had a few seconds to move the camera to the other side of the climbing rope and get it back on the bird. There was no time to do this and reach for the zoom button. Since the idea behind observing from tall trees is to keep watch for ivorybills flying over the treetops, I positioned myself in order to have favorable views in the horizontal directions. Since much of the view below was obstructed by partially leafed-out branches, it was difficult to relocate the bird after it passed the tree. I might not have gotten any footage on the other side of the tree if the camera had been zoomed in. I was 75 feet above the ground in a climbing harness using one hand for balance and the other hand to hold the camera. By the time of the flyunder, I had spent hours carrying climbing gear out to the site, climbing the tree with a backpack loaded with cameras and other gear, and running the video camera.

7-3-08. During the recent visit to the Pearl, I made two trips back up Tree 6 in order to pin down the flight speed and wingspan. I had previously estimated the flight speed to be 14.7 m/s based on crude measurements from the ground. An improved estimate was obtained by returning to the position where the video was obtained and lining up reference points in order to guide assistants to specific positions below, where they placed marker stakes. The improved estimate of the flight speed is 16.2 m/s, which corresponds to 36.3 mph. When this value and the 0.775 m wingspan of the ivorybill are substituted into the leading physics-based flap rate model (which was developed by Nudds et al.), the resulting value of 7.5 Hz is consistent with the flap rate of the bird in the 2008 video. The flap rate of the bird in the 2006 video, which was obtained a short distance away, is 7.5 Hz in two flights. The model of Nudds et al. can be applied to obtain a lower bound for the expected flap rate of the ivorybill without invoking recent sightings or data. Since the ivorybill has a fast and direct flight according to historical accounts, it should be safe to assume that the flight speed of the ivorybill is significantly greater than the maximum flight speed of the pileated, which is 11.6 m/s according to Tobalske. Substituting this value into the model, we conclude that the flap rate of the ivorybill in cruising flight should be significantly greater than 5.4 Hz. The model of Pennycuick (which is discussed in the paper by Nudds et al.) has an entirely different basis, is regarded as the leading empirical model, and predicts a flap rate of 6.5 Hz for the ivorybill. So the two leading flap rate models both predict that the ivorybill has a much greater flap rate than the 3.7 Hz mean flap rate of the pileated.

7-4-08. When analyzing the March 29 video, Bret Tobalske noticed brief pauses in mid upstroke, which is the part of the stroke at which other woodpecker species hold their wings fixed (wing tucking) during intermittent flight. The wing tucks of the pileated seem to be done deliberately and consciously. It has occurred to me that the pauses in the March 29 video seem to be too brief (on the order of 1/30 of a second) to be done consciously. Perhaps they simply correspond to a "hitch" in the stroke.

7-5-08. Now that the details of analyzing the March 29 video have been completed, this would be a good time to post an overview. I was initially confused by the flap style. Like many others, I had concluded from historical accounts of a duck-like flight that the ivorybill has duck-like flaps. It turns out that it actually has flaps like a large woodpecker--the wings are folded close to the body in the middle of the upstroke. Clues to the flap style appearing in two Tanner photos were apparently overlooked for many years until Dalcio Dacol noticed them. The flap rate varies from 6.6 Hz during the approach (15 flaps in 2.27 s) to 7.5 Hz just beyond Tree 6 (4 flaps in 0.533 s). The bird flew about 58 m during a 3.57 s interval, and this corresponds to 16.2 m/s (or 36.3 mph). The observed flap rate is consistent with the 6.5 Hz prediction of the empirical model of Pennycuick. Based on the physics-based model of Nudds et al., the flap rate of the ivorybill would be expected to significantly exceed 5.4 Hz, and the observed flap rate is also consistent with this prediction. Tobalske observed a maximum flight speed of 11.6 m/s for the pileated, which has an intermittent flight. Since the ivorybill would be expected to be significantly faster than the pileated based on historical accounts, the flight speed of the bird in the March 29 video is consistent with ivorybill. The directness of the flight is also consistent with ivorybill. Based on measurements obtained during a recent visit to the site, the wingspan is clearly significantly greater than 24 inches (which rules out kingfisher) and appears to be about 30 inches (which is consistent with ivorybill). There are large patches of white on the dorsal surfaces of the wings. It's clear that those patches account for only a fraction of the wing surfaces since the aspect ratio of the patches is much larger than the aspect ratio of the wings (note that the patches extend for significant distances on both sides of the bends in the wings). There appears to be dark plumage on the leading edges of the wings, which evidently blended in with the dark mud in the background. Two dorsal stripes were observed just before the bird passed Tree 6, and there appears to be white on the back in some of the frames of the video. Just over a minute before the bird appeared flying up the channel, the camera recorded an apparent double rap.

7-6-08. It's often interesting to go back and re-read a book after gaining more experience in a subject. I often find that important points were missed or unappreciated during the first reading. While re-reading Tanner's book, I noticed that he reported that the ivorybill has "rapid" flaps and that the flaps are "particularly hard" at takeoff. These accounts are consistent with other historical accounts (such as Bayard Christy's 1943 account of "deep and rapid" flaps at takeoff), the two leading flap rate models, physiology (a massive bird with low wing surface area would be expected to struggle at takeoff), recent accounts (such as Brian Rolek's report of deep flaps at takeoff), my own observations (unusually deep and rapid flaps seen several times at takeoff), and the flights in the videos that I have obtained (deep and rapid flaps during three takeoffs and rapid flaps during cruising flight).

7-7-08. I noticed something else that I didn't appreciate the first time that I read Tanner's book. Molting seems to be centered around August, which is the only month that I haven't been in the field searching for ivorybills. There seems to be a reasonable chance of finding a feather in late summer. If I visit the Pearl in August, I'll walk through the areas where there have been sightings and keep an eye open for feathers.

7-10-08. Before getting involved in the ivorybill search, I was thinking about taking another trip to the Amazon. I still have the urge to get back down there and have recently been enjoying "A Neotropical Companion," by John Kricher. This book has a nice photo of a tree that consists of a tall bole with many large branches at the top. I was struck by the similarity of that tree and these photos of Tree 0 and Tree 5, which are typical of the tall cypresses in the interior of the Pearl. Cypresses along bayous and other semi-open areas, such as Tree 3, tend to have large branches at lower levels. Trees 0 and 5 are quite impressive compared to the surrounding forest. For example, this photo shows Tree 5 from Tree 2. I discovered Tree 0 while climbing a tree that's a short distance to the east. Its crown was an incredible sight, but I didn't get a photo since the camera was packed away during the climb.

7-11-08. This is a good time to reflect on the 2008 search season for which I have a great deal to be thankful. I had a few bad experiences but nothing comparable to breaking my arm last year or capsizing the kayak in cold water and losing gear two years ago. The worst experiences were my old Ford dying during the drive down in October, the break-in at the house in Waveland in November, and the terrifying free fall from Tree 0 in February. It was exhilarating to spend time observing from tall cypresses. It was exciting to discover an extensive grove of tall cypresses deep in the Pearl that are good candidates for roosting and nesting sites. The most rewarding experience was seeing the dorsal stripes of an ivorybill for the first time as it flew below. The most exciting moments were when Dalcio resolved the apparent paradox regarding the flap style of the bird in the March 29 video, studying an ivorybill in cruising flight and estimating the flight speed for the first time, and discovering that the predictions of the leading flap rate models are in agreement with the data. It was also exciting to see my first bobcat. I enjoyed the visits of birders from several states. The sighting on February 16 with two of the visitors was my first in the Pearl since October 21, 2006. I also enjoyed spending a few days in the field with the LSU searchers. I always enjoy spending time with my friends in Mississippi and Louisiana. It's great to have a local birder like Susan and her sharp eyes involved in the search and to have Gretchen and Tasha involved in the tree climbing. These Louisiana natives love the swamp and aren't afraid to venture deep into it. I also enjoyed the ordinary events, such as pileateds drumming in the distance, kites soaring and calling above, the arrival of warblers and other migrants, otters playing in the bayou, gators submerging like submarines, snakes slithering away, hikes and kayak rides, and the changing of the seasons.

7-13-08. I've been studying the possible double rap and the context of this recording, which is just before the flyunder in the March 29 video. I hear possible double raps fairly regularly in the Pearl (perhaps once per month on average), but I've gotten to the point that I don't pay much attention to the majority of them since they are distant and ambiguous. I don't recall hearing a possible double rap on March 29, but it appears that I did hear it based on the way the camera moved. When the possible double rap occurred, the camera was aimed a little to the left of the direction from which the bird appeared. This was fortunate because the microphone might not have picked it up if the camera had been aimed in the opposite direction. I haven't done any testing of the fidelity of stereo recordings with this camera, but the possible double rap does sound like it comes from the right. Immediately after the possible double rap, I quickly panned the camera to the right and aimed it down the channel. Was this a reaction to hearing the possible double rap and detecting its direction? It's likely that I did hear it since the camera picked it up. I've previously heard possible double raps that the camera did not pick up. The recording is weak, but it sounds quite good to me. It also sounds similar to the possible double rap that I heard in the Choctawhatchee on March 6.

7-17-08. I noticed something interesting in sketches by Julie Zickefoose of the flights of a pileated and an ivorybill. She correctly depicts the pileated flight as undulating and the ivorybill flight as direct and has the pileated folding its wings close to the body during the upstroke. Like many others (including me), Julie apparently misinterpreted accounts of a duck-like flight to include the flap style and doesn't show the ivorybill folding its wings close to the body during the upstroke.

7-18-08. The bird had this view as it approached Tree 6 on March 29. I wonder if it noticed me just below the pulley, which is marked by the red box.

7-20-08. It was on this date last year that I completed a very long search season. It was only because of the excitement of implementing the tree climbing approach that I was able to hold out so long.

7-22-08. I wonder how many birders have seen all 23 woodpeckers of North America:

Lewis's Woodpecker, Red-headed Woodpecker, Acorn Woodpecker, Gila Woodpecker, Golden-fronted Woodpecker, Red-bellied Woodpecker, Yellow-bellied Sapsucker, Red-naped Sapsucker, Red-breasted Sapsucker, Williamson's Sapsucker, Ladder-backed Woodpecker, Nuttall's Woodpecker, Downy Woodpecker, Hairy Woodpecker, Arizona Woodpecker, Red-cockaded Woodpecker, White-headed Woodpecker, Three-toed Woodpecker, Black-backed Woodpecker, Northern Flicker, Gilded Flicker, Pileated Woodpecker, Ivory-billed Woodpecker

I've seen them all, and the ivorybill isn't the only one that was hard to find.

7-23-08. A rumor that live-fire exercises had begun in the Pearl has been confirmed by an official at Stennis, who informed me that machine guns with real bullets, live grenades, and live mortars are being used. This activity is taking place in good habitat near where most of the sightings have occurred during the past few years. It's disgraceful that such a thing is happening in an area with a critically endangered species. It's even more disgraceful that birders and ornithologists are allowing it to happen.

7-28-08. When Bret Tobalske analyzed (and digitized) the March 29 video, he noticed brief pauses (or bounds) during the middle of the upstroke and produced this graph that illustrates them. Such pauses are typical in the flaps of woodpeckers, but in this case the pauses seem to be too brief to be done consciously or to play a significant role in the flight mechanics. One of the authors of the landmark paper on the Strouhal-based flap rate model, Adrian Thomas, may have provided the answer to this mystery. According to Adrian, birds with direct flights (such as the ivorybill) tend to retain vestiges of an intermittent flight if they belong to a family of birds that mainly consists of intermittent fliers. The ivorybill belongs to such a family, and this explanation seems to be a perfect fit.

8-1-08. I came across the copy of Jerome Jackson's book that I read when it first came out. Jackson mentions that, "As with other birds, flight ends with a quick, upward swoop, using the wings to brake." While it's true that other species swoop to some degree, characterizing the swooping of an ivorybill as typical bird behavior is like characterizing the redwood as a typical tree. The swooping of an ivorybill is spectacular as can be seen in the 2007 video. In upward swoops, the wings are not used for braking, which is an inefficient way of landing. The purpose of upward swoops is to convert kinetic energy (speed) into potential energy (height), which saves valuable calories. In this upward swoop, for example, the wings are gently closed as the bird comes to a stop at the top of the swoop, with little or no braking. Jackson, who recently claimed that no good scientific evidence of the ivorybill has been obtained, quotes Tanner's description of rapid wingbeats in a direct cruising flight and loud wingbeats at takeoff. The 2008 video shows a large woodpecker in a direct cruising flight with a flap rate much too high for a pileated. The loudness of the wingbeats at takeoff must have a simple explanation, and what could be more simple than the fact that the flaps are deep and rapid as is clearly evident in the 2006 and 2007 videos?

8-2-08. When the bird took off to the left in the 2006 video, it came into view near the green marker in this photo and took 0.533 seconds to cover the distance between the red markers. Since the flight path appeared to be nearly normal to the line of sight, an estimate for the average flight speed can be obtained using the angular distance between the red markers and the distance to the bird (128 meters). From the properties of the camera and the focal length, Dave from Michigan determined that the horizontal field of view of the uncropped photo is 50.7 degrees, from which it follows that the angle between the red markers is about 2 degrees and the average flight speed is 8.5 m/s. When the bird reached the first red marker, it had only been flying for 0.783 seconds and was still using deep flaps, which suggests that it was still well below cruising speed.

8-3-08. There exists footage of an Imperial Woodpecker, and the bird is in flight according to what I have heard. Why haven't the details been made public? The flap rate, flight speed, and flap style might shed light on the ivorybill.

8-5-08. Some of the photos from the Pearl have been converted to art using the "cutout" option in Photoshop.

8-8-08. When I obtained the Choctawhatchee video, the birds seemed to have been long gone by the time another searcher arrived at the scene. I decided to search through that footage and found a possible double rap (it takes good speakers to hear the second rap). It's plausible that the birds remained within earshot of a double rap since they remained in the same general area after another searcher flushed them the day before.

8-12-08. I just finished reading John Gribbin's "The Scientists," which contains many fascinating accounts of scientific discovery since Copernicus. It was refreshing to read about scientists who recognized that progress can often be made without pretty pictures. For example, John Michell was aware that black holes can be studied through their gravitational influence on visible objects in 1783, and Thomas Young estimated the size of the water molecule using surface tension in 1816. There are many other examples, including on-going efforts to discover extra-solar planets.

8-13-08. I started looking forward to the molting season after becoming aware of Pennycuick's model, which predicts increased flap rate with decreased wing surface area. I have recently observed crows with missing primaries, and they do indeed appear to have higher than normal flap rates (as I had recalled from previous years).

8-20-08. I recently read "The Universe in a Mirror: The Saga of the Hubble Space Telescope and the Visionaries Who Built It," by Robert Zimmerman. With a vantage point above the atmosphere, Hubble opened up a new window for astronomers, who eagerly huddled around a computer screen awaiting the first images. A few years later, the first Hubble images of the impacts of the fragments of Comet Shoemaker-Levy/9 were anticipated with a similar level of excitement. I'll never forget watching that event on the NASA Channel. A panel discusson led by Gene Shoemaker was interrupted by Heidi Hammel (a classmate of mine at MIT), who brought out a copy of the first image from the impact of the first comet fragment. Until that point, it wasn't clear what (if anything) would be detectable from the impacts. The image showed that it was going to be a spectacular and historic week in astronomy, and there were high fives all around. This is what science is all about--discovering the wonders of nature. I don't see how any scientist interested in the ivorybill could avoid being as passionate about revealing the secrets of this species as astronomers are about the secrets that have been revealed by Hubble. Before the big news came from Arkansas, it seemed that many of the secrets of the ivorybill were lost forever. For example, historical accounts weren't sufficiently detailed to fully understand the flight of this species but were tantalizing enough to make me passionately desire that knowledge, which was recently snatched from the jaws of oblivion.

8-21-08. Mark from New York pointed out that Agey and Heinzmann had a much higher encounter rate than anyone has had in recent years. This was probably due to the fact that they located an active cavity (from which an ivorybill feather was obtained after the tree fell). For a brief period in 2006, I had an extraordinary flurry of activity in the Pearl, with encounters early in the morning on February 16, 17, 18, and 20. Maybe there was an active roost in that area.

8-29-08. I spotted the ivorybill far down the channel on March 29. Based on its large size and fast and direct flight over water, I immediately assumed it was a Wood Duck. I didn't notice anything that contradicted this assessment until taking my eye away from the viewfinder in order to move the camera to the other side of the climbing rope. At that point, the bird was nearly directly below, and I caught a glimpse of the dorsal stripes. Since it was an overcast morning, it's not clear that I would have noticed field marks much earlier even if I hadn't been operating the camera. This experience really drove home the point that it would be easy for a duck hunter to mistakenly shoot an ivorybill. Although duck hunters are highly skilled at identifying waterfowl in flight, it's challenging to identify a bird flying at high speed in poor light.

9-1-08. Although the Pearl ivorybills survived Katrina, I've been holding my breath for the past few days, hoping the Pearl would avoid another brutal blow. Fortunately, Gustav turned out to be weaker than Katrina and came ashore further west.

9-2-08. I recently listened to the recording of the wingbeats of an ivorybill taking off in flight in the Singer Tract. Since loud wingbeats are typical of large birds, I used to wonder why there was so much interest in the sound of ivorybill wingbeats. I now realize that it's because the ivorybill has unusually deep and rapid flaps at takeoff, and the sound of the wingbeats in the Singer Tract recording is indeed extraordinary. On February 17, 2006, I heard the wingbeats of an ivorybill that flushed from close range on the other side of a fallen tree. I noticed that the wingbeats had an impressive sound, but I didn't have a copy of the Singer Tract recording to listen to for comparison. Oh, how I wish that I had recorded those wingbeats. Thinking about the sound of wingbeats, I looked back on my log for the day late last year (December 26) when I heard loud wingbeats after hearing loud pounding sounds in the woods. The bird came from the direction of the pounding sounds and flew behind me (like the encounter depicted in the cartoon at the top of this page). In the same area, I heard a loud rap on January 14, found extensive foraging sign on January 17, and obtained a video of an ivorybill in flight on March 29.

9-5-08. Since many months may pass between ivorybill encounters that typically last for only a few seconds, it's hard to keep a camera running at all times. The fatigue and monotony that are inevitable after extended periods in the field can also lead to missed opportunities. I was totally unprepared for the sighting on February 16, 2008. Besides not having a camera ready, I wasn't mentally sharp after yet another long day in the field. I took my eye off the location where the bird landed in order to ask the other observers what they saw, and this caused me to miss the swooping takeoff that Susan Epps observed. Lack of experience with the ivorybill is another factor that can lead to missed opportunities. When I obtained the 2006 video, I wasn't aware that ivorybills are wily enough to keep watch on a human from a distance. I could have gotten some great footage that day if I knew then what I know now. When I obtained the 2008 video, I had no idea that an ivorybill would fly like a duck low over the water. I expected the cruising flight to be over the treetops (which it may indeed be in many cases). Since the sound of an ivorybill foraging or building a cavity has never been recorded, I don't have much confidence in identifying ivorybills based on such sounds. I have heard loud pounding sounds three times in the Pearl and suspect that at least two of them were ivorybills. The loud raps that I heard on December 26, 2007, were followed by a large bird taking off from that area with loud wingbeats. I mistook the sounds for someone pounding with a hammer, but that area is only accessible by water and there were no boats in the area. I now realize that it was probably an ivorybill.

9-12-08. I'm in the middle of reading "A Man on the Moon," by Andrew Chaikin, which brought back memories of standing in my front yard and marvelling at the sight of Apollo 11 taking off on July 16, 1969. The only comparable experiences in my life have been seeing the Ivory-billed Woodpecker, observing a total eclipse in Mexico in 1991, and descending from two locations in the Peruvian Andes to get my first glimpse of the Maranon (one of the branches of the Amazon) and to see Manu Road leading toward the lowland rainforest.

9-14-08. The flap rate of the bird in the 2008 video is in agreement with the two leading flap rate models. One of the models relates body mass, wingspan, and wing surface area to flap rate. The other model relates wingspan and flight speed to flap rate. It should also be possible to model swooping takeoffs and landings in terms of these parameters. Many species swoop, but I've never seen anything swoop as dramatically as the ivorybill, and this is clearly due to the high body mass and low wing surface area. The swoops captured in the 2007 video are very steep and involve large changes in altitude.

A day-to-day log of the 2009 search season is posted here.