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Sunset Sighting (Possible): April 27, 2018 – Updated x2

Update 2, May 2, 2018: I have always made being forthright with my readers a priority. I chose to revert this post to draft in order to pause and reflect. Based on recent events and the prematurity of the post and first update, I think some changes in my approach to blogging are in order, something I will address in a future post.

I have decided to restore the initial post and the first update to public view because I owe it to my readers and think it’s the right thing to do.

As several people have pointed out, I was too hasty in “accepting” that whatever I saw on April 27 was a Pileated Woodpecker. My description of what I heard and saw on April 27th was inconsistent with Pileated, and I stand by the description. My observations of a Pileated Woodpecker going to roost on the 28th differed from what I heard and saw on the 27th. From an email sent early in the morning on the 29th:

A PIWO came in, overhead, either silently or very soft wingbeats when it landed. It drummed a couple of times and went to roost about 20 minutes before sunset but continued tapping from inside the cavity for about five minutes. (The bird on the 27th had come in no more than 2 minutes before sunset.) I hope to have gotten some decent photos. All PIWO sounds in the area stopped ~8 minutes prior to sunset.

It strikes me this morning that this behavior was somewhat different than the other bird’s; last night’s PIWO must have seen me, but my presence didn’t prevent it from coming very close and going directly to the roost. The other bird appeared to have been spooked by my presence.

Here’s what I know: I am confident I heard the wing sounds, as described, and am personally convinced that what I saw was a large woodpecker. I’m also confident I saw a PIWO going to roost near where the other event took place, on the following night, approximately 20 minutes earlier relative to sunset. I have the pictures to prove that. The rest is inference.

It’s easy (for me at least) to get overly enthusiastic about possible encounters; its also easy for me to turn around and look for ways to discount or discredit them in my own mind. To some degree, this is a good thing and probably comes with the territory, unless you’re delusional or prone to self-inflation. Still, there are points at which enthusiasm and skepticism become unhealthy. This applies to personal enthusiasm, self-skepticism, and to the way others respond to ivorybill claims. The Internet environment feeds unhealthy responses.

Regardless of anything else, this was a productive trip. We have six cameras deployed (thanks to Erik, Geoffrey, and Jay for contributing a new cam each) – five on hickories, either recently dead or in decline, and one a big sweet gum stub, three years dead, with some very recent bark scaling and signs of beetle infestation, in an earlier stage of decay than the Singer Tract tree where Pearson observed ivorybills feeding in the early 1930s. While this work could well be something other than ivorybill, and the bark is loose, it seems worth watching for a while.

I have been monitoring this stub since the top came down; in fact, we deployed a camera there in the spring of 2015, only to lose it to flooding. (The new deployment is higher on a nearby tree.) This suggests that our main strategy for camera trap placement – finding potential feeding trees and stubs in advance of any large woodpecker activity requires a multi-year commitment.

Even in this impatient world, patience is a virtue.

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Update, April 30, 2018: Based on an observation last night of a Pileated Woodpecker going to roost in the sycamore cavity shown below and an exploration of the clearcut area this afternoon, I strongly suspect the bird I saw on the 27th was also a Pileated Woodpecker. I still have trouble squaring what I heard and saw with Pileated, but the circumstances suggest that’s what it was. I’m opting to leave the content up, with this correction, in the interest of transparency. I will undoubtedly have more to say on this in the near future. Accepting that the bird in question was a Pileated Woodpecker in no way affects my view that the sounds Matt recorded in March and the ones Matt and Phil recorded in March 2017 were made by Ivory-billed Woodpeckers.

Original Post: I initially planned on including this sighting in a complete trip report but have decided to write it up and post it now as a kind of dispatch from the field. I may include some further commentary and imagery when I post the full report sometime within the next couple of weeks.

I expect this post will attract a number of new readers, so I want to preface the account with a few comments. Friends, associates, and many regular readers probably know that I’ve had a handful of possible sightings over the past 11 years, a total of seven, if memory serves. This over many hundreds of hours in the field. With the exception of the November 2009 sighting in the location where a suggestive trail cam photo was obtained a week later, I have not had a high level of confidence in these possibles and have rejected two of them as the product of wishful thinking. Last night’s experience was altogether different, even when compared to the 2009 possible, as was my reaction to it.

Here’s what I wrote to my inner circle approximately one hour after the sighting. I have made a few minor edits for clarity and to protect the location and have added revisions/corrections/additional comments in bold italics:

I’ve already shared this with Matt and Patricia, and I dictated the details into my recording device (which has been a little buggy) immediately after the incident. I haven’t listened yet, and this will include some additional details. (Any substantive differences between the recorded comments and the contents included here will be addressed in the full trip report, though I don’t anticipate there being any.)

I arrived at the spot where Matt made the recordings last month at approximately 6:40 PM (I was in the area before sunrise too). I sat facing WSW; the area directly across the water from me was recently clearcut. There are trees along the bank with an open expanse behind. Sunset was at ***. The events described took place between 2 minutes before and three minutes after sunset, by which time I had pretty much given up hope that anything interesting would happen.

There were two cypress trees across the water from me; one perhaps 1’ DBH and the other over 2’. I did not consciously register a bird flying in to the larger cypress, but I suspect I sensed it. (In retrospect, I wonder if I unconsciously heard it flying in, as my focus for the evening was on listening.) In any event, my first conscious observation was of a large woodpecker taking off from the backside of the tree. My impression was that it had flown in and took off almost immediately on seeing me. I was able to hear the wingbeats, which sounded stiff and wooden, not muffled and whooshing like the PIWOs I’ve heard. (I’ve only heard PIWO wingbeats when birds were directly overhead or when I’ve flushed them at very close range.) I was looking more or less directly into the remaining sunlight (the sun had long since gone below the tree line), and the light was very low, so I could only see a silhouette. The wings were long and narrow, and the overall GISS (General Impression, Size, and Shape) was not PIWO. After several flaps, the bird went into a glide, and I lost sight of it very soon thereafter. I’d estimate I had eyes on it for 2-3 seconds.

I continued to watch the area when what I took to be the same bird flew in to some hardwoods perhaps 20 yards SSW and 10 yards inland from the cypresses. I heard the wingbeats again but could not locate the bird in the trees; darkness was falling rapidly. I made a split second decision to try some Pileated playback to see whether it would provoke a response. PIWOs had been calling and drumming until a few minutes before this incident. I did several rounds of playback using the iBird Pro app and got no response or visible reaction. At this point, I checked the time, and it was three minutes past sunset.

FWIW, I find this sighting more personally compelling for IBWO than any of my previous possibles, including the one in the old search area where we got the trail cam photo a week later. (As implied by the updates, my view on this has shifted – as I not only heard wingbeats but saw white on the wings and the suggestive trail cam image obtained a week later adds support; there’s a closer temporal association than there is with the recordings Matt obtained just over a month before.) Some of this is gut feeling, but the wingbeats (audible at 30-50 yards) wing and body shape, the glide, and the lack of response to PIWO playback (though the hour was late), all contribute to my interpretation. Would I bet my life that this was an ivory bill? No. Will I add IBWO to my life list? I’m not sure, but I’m closer to doing so than I ever have been.

So there it is. I’m going back to the same vicinity tomorrow morning, though I may go to the edge of the clear cut.
The cavity in the attached image may also be of interest. It is likely fairly fresh, as Matt would likely have seen it last month had it been there then. I staked it out this morning and nothing emerged. It is southeast of where I was stationed.

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I returned to the area this morning and found an additional interesting cavity in a sycamore about twenty yards south of the oak and hickory where I last saw the bird.

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This cavity (in a sycamore) looks deceptively small in the photo due to the large diameter of the trunk. My field impression was that it was easily big enough, and I’m conservative in making these judgments.

It was either not used overnight or had been vacated by the time I arrived, as I had encountered an almost uncanny delay that caused me to miss the sunrise. I reached the end of a long gravel road, about a quarter mile from my planned stakeout spot and ran into a turkey hunter. As so often happens, a conversation ensued, and to my astonishment, he told me his name was Kuhn. I asked if he was related to the Tallulah Kuhns, and indeed he was; he was far from home himself, and we were nowhere near Tallulah. He had known his cousin (not sure what degree) Edith Whitehead and was aware of her father’s work on pecan agronomy and hybridization, though he knew nothing of the ivorybill and his relative’s central role in the story.  What an extraordinary (almost in the Sagan sense) coincidence.

A final note, while I saw no field marks, the wingbeats are an acoustic equivalent. As Fredrik Bryntesson reminded me, Tanner wrote about the sound very explicitly. I knew this in general terms, of course, but the actual language took me a little by surprise:

A description of the wing sounds is found in Tanner’s monograph, p. 58: “The wing-feathers of Ivory-bills are stiff and hard, thus making their flight noisy. In the initial flight, when the wings are beaten particularly hard, they make quite a loud, wooden, fluttering sound, so much so that I often nicknamed the birds ‘wooden-wings’; it is the loudest wing-sound I have ever heard from any bird of that size excepting the grouse. At times when the birds happened to swoop past me, I heard a pronounced swishing whistle.”

I’ll leave it there for now.

 

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Trip Report: April 26-May 1, 2017

I returned to the search area last week and spent as much time as I could in the field. The trip was generally uneventful, and conditions – strong winds, rain, and high water – limited my field time. Woodpeckers are getting quieter generally; full leaf out, heat (temperatures in the high 80s on the 26th, 27th, and 28th), and abundant mosquitoes make things even more difficult at this time of year; nevertheless, I’m planning one more trip before summer.

On the 26th, I hiked to hickory stub that currently has two cameras trained on it, as one camera needed securing. There were no signs of woodpecker activity on the stub. This beautiful Great Egret in a beautiful spot was a highlight. There were Little Blue Herons in the vicinity too, but I couldn’t get a clear shot, too much mud and intervening vegetation.

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On the 27th, I arrived at the “listening point” (where the March recordings were made) shortly after sunrise. I opted to sit quietly, rather than doing playback or ADKs. I did not see or hear anything.

I met up with Steve Pagans at around 10 am. Since water levels were low, we were able to get closer to the snag with the cavity that I found last month. I spotted a second cavity higher on the stub, on the opposite side. IMGP4571 (1)

These cavities are large, similar in size, shape, and unusual appearance. While I suspect they are no longer active roosts, we will put a camera on the snag in June, if it’s feasible to do so. The nest John Dennis found in Cuba appeared to have two entrance holes, although Dennis thought one might be too small.

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On the hike out, I spotted this wolf spider with her young on her back.

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On the 29th, Steve and I visited one of the less accessible parts of the search area. It is an impressive patch of forest, with some oaks and sweet gums approaching or surpassing 5′ DBH. The sweet gum below is probably the largest single trunked gum we’ve found.

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Reminiscent of the Singer Tract.

Predicted wind speeds were 15-20 mph, and the gusts were undoubtedly stronger, so birds were not very active. The gusts were often unnerving, and a couple of large limbs fell, uncomfortably close to us, while we were stopped for lunch.

The forecast for the 30th was for even stronger winds, with thunderstorms in the afternoon. We decided to play it safe and stay out of the woods. Steve went home, and I spent part of the day driving scouting a large patch of nearby forest by car, but I wasn’t able to reach the bottomland area that had intrigued me on Google Earth.

The rains didn’t arrive until evening, but they were very heavy, with 3-4″ overnight. Thunderstorms continued until mid-morning on the 1st, so I didn’t venture out until about 10:30. Conditions were cool and cloudy, and everything was soaking wet. My movements were limited by high water levels; these continued to rise during the four hours I spent in the field. Avian activity was again minimal. Coming across this rattlesnake, the third or fourth I’ve found over the years, was the day’s highlight.

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On May 2nd, my last field day, I spent the early morning trying to get to the hickory stub and trail cams. Water levels were too high, so I returned to my car and drove to a more accessible location. While I have been concentrating on it less this season, there have been a number of possible contacts in this area, and we have found abundant sweet gum scaling there every year. As has been discussed in several recent posts, classic, ‘Tanneresque’ high branch scaling on freshly dead sweet gums is not necessarily inconsistent with Pileated Woodpecker.

Still, I found some very dramatic work on the dead fork of a dying gum. Phil and I first found this tree in February, but most of the scaling has taken place since then. Of particular note were the enormous bark chips found at the base, again all removed since the end of January. My hat, which is shown for scale, is 12.5″ x 12″. Note that this scaling involves some of the largest limbs. Since some gum balls are still attached to the dead limbs, I think it’s safe to assume that the bark remains relatively tight; the scaling also looks generally clean, something that I find suggestive of ivorybill. To the best of my recollection, the bark chips are the largest I’ve ever found from sweet gum limbs.

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Later that morning, I found a mildly intriguing cavity in a small sweet gum (~18″ DBH). While it’s almost surely PIWO, I’m including it because the shape and skewed angle are somewhat interesting and also to illustrate that even smaller trees can host substantial cavities. The original image was badly backlit, so I’ve brightened it and rendered it in black and white to make the cavity easier to see. Referencing Dennis again, he estimated the diameter of his Cuban nest tree at 12″. While DNA evidence suggests the Cuban IBWO is/was a different species, more closely related to the Imperial than to the US IBWO, the conditions under which Dennis found a breeding pair seem relevant to the survival of the North American species, and the ‘old growth specialist’ caricature:

There was a sprinkling of deciduous trees, some quite large. Although this region had been heavily logged and burned over as well, growth was quite luxuriant in spots. A watercourse, as well as the generally rugged terrain, had prevented a clean sweep of all the timber. The pine  trees, on the whole, were limited to less than five inches in diameter.

There may be more on this in an upcoming post.

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Rare Ivory-billed Woodpecker Images

 

 

My visits to Cornell’s Kroch Library, where the Rare and Manuscript Collections are housed, have been very productive. In addition to the last letter to Tanner pertaining to the Singer Tract ivorybills quoted at length here, I’ve come across several little known ivorybill images, some better quality reproductions of the plates in Tanner, and some additional hints about ivorybill foraging excavations that I’ll discuss in a future post. I suspect that all of the images below are actually stills from the 1935 film footage that has been lost save for a few minutes. To see it, go here and start at 14:00. To the best of my knowledge, these images have not previously been published as stills, and a couple of the frames may never have been publicly available.

The first image is similar to the one that appears on Page 82 0f  The Race to Save the Lord God Bird.  This is a sequence (that apparently has been lost) in which the birds are changing places on the nest. A third image that follows the first two appears on p. 120 of The Race . . . A colorized version, at once gorgeous and crude and sadly somewhat damaged, is also included here; it’s reproduced in black and white in Jackson (p. 27).

I think the bird in the remaining frames is the male. In the second frame, he may be engaging in the motion described by Tanner, “. . . jerking as though working food from the back of its mouth.” the next frame shows the him peering into the cavity. These two images are clips from the surviving footage. The final shot may have come from a lost piece of film, since a remaining clip, filmed from a similar angle doesn’t include it.

In addition to the images posted below, two figures in Tanner’s dissertation include unpublished photos from 1938 – one of a male at the nest cavity and the other of a juvenile peering out of it. Those images may also be included in a future post. All four pictures below were taken with my iPhone. I have a high resolution scan of the fourth on order, since it is one of the best representations of presumed ivorybill excavation available. Images are Courtesy of the Division of Rare and Manuscript Collections, Cornell University Library.

 

 

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Trip Report, Part One: March 31-April 5, 2015

As always, my time in our search area was very productive – inspiring new insights and ideas and producing suggestive but inconclusive evidence that Ivory-billed Woodpeckers are present in this location and have been for years. The weather was considerably more cooperative this trip than on the two or three preceding ones, although temperatures edged toward the uncomfortable – mid 80s and humid from Tuesday-Friday – and rain limited field time on Saturday and Sunday. I was alone from Tuesday-Thursday, and Frank Wiley joined me from Friday-Sunday. Later this week, I’ll post a day-to-day log that includes more about possible encounters and some additional images,

For reasons that should become clear, we are starting to think there may be a home range in an area of over four square miles (and possibly considerably more than that), much of which we have not yet explored, and some of which is very difficult to reach – a two mile walk from the nearest road and bisected by deep sloughs and streams. We have some reason to suspect that this range has been used for a number of years. This is in very mature bottomland forest, logged between 1905 and 1915, and it includes the stand of sweet gums where we found a cavity cluster last year.

Also on this trip, we did more experimenting with playbacks; I actually began the experiment shortly before I left for Louisiana, with a Pileated Woodpecker in my yard outside New York City. She responded with considerable agitation to my playback of Pileated calls and drums – calling and flying over at very close range while looking directly at me. She did not react at all to playback of ivorybill calls and pounding from the Singer Tract (the iBird Pro selections). Several species in our search area seem to react to ivorybill playbacks. Pileated, Red-bellied, and Red-headed Woodpeckers frequently react with drumming and scolding. In one instance, a calling Pileated Woodpecker went silent and flew away immediately after a playback. Barred Owls will often call immediately after, as will American Crows. In one case, a pair of crows came in to within 80 feet, apparently to investigate; in another, a Red-shouldered Hawk did the same.

There were three instances of possible ivorybill interaction with or response to playback. Two of them were very weak possibles, meriting only this passing mention. The third was a little more interesting and will be discussed in the day-by-day account. We will continue the experiment, both in Louisiana and New York (to see if and how various species react). We’ve recently been informed, by “Motiheal” from ibwo.net, that a Red-headed Woodpecker in Virginia approached in response to the playback of five kents.

One of the reasons we’re optimistic about having pinpointed a home range is the abundance of feeding sign in the area. In addition to the work sign from this area discussed in previous posts, there’s an abundance of older work, like this scaling on a hickory snag. OldHickory3 oldhickory2

Extensive scaling on an older hickory snag. Work goes from near the base to near the top. Atypically, some of the work at the base appears to be more recent than the rest.

Extensive scaling on an older hickory snag. Work goes from near the base to near the top. Atypically, some of the work at the base appears to be more recent than the rest. While the work is not fresh, and the bark has started to loosen, it is still within the decay stage described by Tanner as being preferred by ivorybills, as shown by the presence of twigs.

According to Tanner (p. 47), “Trees and limbs almost two years dead have lost almost all twigs, some small branches, and bark is loosened on some small branches.” Of course, the decay process is not as linear as Tanner’s description implies, and scaling of bark itself hastens the loosening of whatever remains. Thus, on scaled branches and boles, bark is likely to have loosened considerably unless the work is very fresh. Still, the presence of leaves and/or twigs is a strong indicator of recent death, perhaps even more so on blowdown, for which the decay process is likely hastened by proximity to the ground. In terms of more recent work, I found two sweet gums with sign on large high limbs, perhaps the most dramatic scaling that closely matches Tanner’s description we’ve found to date. Not only is it very extensive; the scaled limbs are quite recently dead. While it’s not possible to test the tightness of the bark, the presence of leaves in the case of the more recent scaling and twigs with buds in the case of the somewhat older work suggest that the limbs died within a six months to, at most, two years. SweetGum1 SweetGum2 It has been suggested that ivorybills are largely birds of the canopy that seldom if ever feed near the ground and that this behavior might account for the difficulty in obtaining clear photographs. Despite the fact that Allen and Kellogg observed a female bird feeding on the ground like a Flicker, and Tanner himself reported observations of foraging close to the ground, the idea that the species is limited to the canopy has become a kind of conventional wisdom. As I’ve discussed in previous posts, I don’t accept this notion and much of the feeding sign we’ve found has been low on standing trees and snags and on blowdown or slash. In the last trip report, I discussed feeding sign found on recently downed sweet gums (just outside of what we believe to be the hot zone, although possibly within it if it is larger than we currently suspect). On this trip, I found over two dozen examples of extensive bark scaling on downed sweet gum tops and limbs. IMG_0888 DSC00076 DSC00070 DSC00074 This work was so commonplace that photographing additional examples seemed redundant. In all cases, the blowdowns were recent and involved very freshly dead wood. At least some leaves were still attached, making it likely that these limbs and tops had fallen in the last six months to one year. In the hot zone, I found only two sweet gum tops or large limbs that had not been scaled. Most of the scaling was recent to very fresh, probably one or two days old in one instance (unfortunately, it had rained the night before, so any scat had been washed away.) I do not believe that all of this is the work of ivorybills. Nonetheless, I suspect that much of it is, due to its abundance and extensiveness and in light of Tanner’s study and the preference he found in the Singer Tract ivorybills for recently dead and dying sweet gums (this even though I believe Tanner overstated this preference and did not sufficiently account for specific conditions in the Singer Tract).

I did not find this type of work in brief visits to areas outside the hot zone, where it was ubiquitous; nor have I seen anything quite like it elsewhere. I did not see anything like it on other species of downed trees; the only partial exception was some scaling on longer dead parts of a live downed hickory. As an aside, it’s worth mentioning that the species of hickory in our area were not present in the Singer Tract, although their congeners, pecans and water hickory were. Unlike Tanner, we’re finding scaling on hickories that likely exceeds their relative abundance. We’re also finding considerably less scaling on various oak species.

In addition to the work on freshly downed sweet gums, I found two standing, recently dead young sweet gums that had been worked on in unusual ways. Both showed signs of infestation by insects that bored into the heartwood. Both had been very heavily scaled, one with minimal excavation only around the insect tunnels. The other had been hacked up in a way that, in the words of several people, looked as if someone had taken a hatchet to it; the wood was hard and not at all punky. Whatever did this work chopped through a small branch to the point where it broke off and almost severed the top of the tree as well.

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Close-up of 2" diameter limb that apparently broke off while being fed upon

Close-up of 2″ diameter limb that apparently broke off while being fed upon

In his report on Cuban ivorybills, George Lamb described something similar:

Soon after we observed a female ivory-bill . . . feeding on the dead branch of a Hilacho tree (Torrubia obtusata) in a small stand of hardwoods. Suddenly the branch broke off while she was still perched on it . . . The Hilacho limb previously mentioned as breaking while being fed on, represents a type of feeding which was neither scaling nor digging. The limb was vertical and had probably originally been about three inches in diameter. Possibly it had once been scaled, but when recovered showed evidence of feeding to the extent that hardly anything was left. The wood was very punky and hand been chipped away from the perimeter to of the limb all along it’s 2 1/2 foot length. The chips, some of which we gathered, were long and splintery appearing, and were riddled with beetle larvae “tunnels”. 

Our broken branch is approximately 2″ in diameter, while the top appears to be more than 3″. Unlike the Hilacho tree, the wood on this sweet gum was hard, not punky.

While I suspect that some of the work on these trees, the very targeted work on the limbs (small rectangular scaling/digging), may have been done by Hairy Woodpeckers, the bulk of it is extremely unusual, inconsistent with any Pileated Woodpecker work I’ve ever seen and with Tanner’s description of that species’ foraging preference for longer dead wood; the type of prey is consistent with what would be expected for ivorybills. While the work on ‘hatcheted’ sapling doesn’t meet the diagnostic criteria we’ve developed over the years, we think it highly likely that this is Ivory-billed Woodpecker work. The scaling on the other small sapling is generally consistent with our criteria, although it has some very limited excavation, clearly aimed at expanding existing tunnels, rather than digging into the wood in the manner typical of Pileated Woodpeckers. Top of Snag LittleSapling ExitTunnelExpanded IMG_0876_2 Again, from the Lamb report: At one point she was only about 25 feet away while she was feeding around the base of a small pine. She began working “barking” this tree around 30 inches from the ground and slowly worked her way up to the top.

Stay tuned for the second installment, which will also include details of a sighting Frank Wiley had on Friday, April 3.


Additional Thoughts on Behavior and Rapid Evolution

I’d like to address an interesting post from “Sidewinder” on the Ivory-billed Woodpecker Researchers’ Forum on the rapid evolution question. His key points:

“Cyberthrush and others have suggested that natural selection has favored high levels of wariness and human avoidance in the IBWO. This position assumes that the change has a genetic rather than experiential (learned) basis. I have questioned this possibility based on the simple fact that behavior is usually one of the fastest traits to evolve. I have no problem with intense human predation on the IBWO resulting in increased vigilance among the surviving remnant, but if the IBWO persists, human predation has been absent now for dozens of generations. While many studies demonstrate that predation pressure can select for increased wariness in animals, what about the inverse? Can multiple generations of relaxed selection over a relatively short term (<100 years) result in relaxed vigilance?”

He concludes that the evidence is mixed and that the, “ . . . findings do not really support or refute Cyberthrush’s hypothesis. Clearly, we need more study–particularly of birds–to learn whether avoidance of humans might persist for many generations after selective pressure (predation) no longer exists to maintain vigilance. In the meanwhile, let’s acknowledge the highly tentative nature of this hypothesis.”

I hadn’t considered relaxed vigilance as a possibility, and it’s an interesting idea. With regard to the general evolved vigilance hypothesis, it’s certainly possible; I just don’t see it as being necessary to explain the difficulty of detection. I think normal wariness, difficult habitat, and extremely low densities suffice.

The hypothesis that the IBWO would dramatically change its foraging behavior, which is to a large degree morphologically determined, is considerably more extreme than the idea that the species became more wary. I have taken issue with the notion (or simplistic reading of Tanner), that the species is (or was) an extreme specialist, but its anatomy and historic range point to some degree of specialization – considerably more than exists in the PIWO.

I suspect that Tanner significantly overstated matters when writing about the canopy and high branch work, but even Tanner made it clear that IBWOs foraged at all levels. Some of the known prey species primarily feed and develop in the boles and in some cases quite near the ground (H. polita, for example). I suspect the high branch foraging Tanner observed was for larvae that he dismissed as being unsuitable because they feed on longer dead wood – Tenebrionidae in particular, although there’s no evidence from stomach contents to support this idea. The larvae we found under bark of this downed sweet gum have been id’d as belonging to that genus, and the tree was not very long dead.

One of the Singer Tract (in a pin oak stub, Mack’s Bayou) was in a clearing.

Mack's Bayou Ivorybill nest tree. Courtesy of the Division of Rare and Manuscript Collections, Cornell University Library

Mack’s Bayou nest tree. Courtesy of the Division of Rare and Manuscript Collections, Cornell University Library

John Dennis’s photos of Cuban IBWOs at a nest also appear to be from a very open area (and even if the Cuban IBWO is a different species, it’s a very close relative, and the hunting pressure there was almost certainly equal, if not more intense.) These seem odd nest locations for a bird that has rapidly evolved to hide in the canopy.

It’s also pretty clear to me that the John’s Bayou birds learned to tolerate human presence, while other IBWOs in the Singer Tract did not. As I’ve pointed out in several posts, Tanner and Kuhn (to a lesser extent) had a difficult time finding ivorybills in other parts of the Tract. This also suggests a behavioral rather than a genetic basis for the wariness or at the very least a substantial behavioral component.


More Minutiae – Habitat Quality and Population Density in the Singer Tract

Last week I linked to this image and pointed out that the caption described it as the “Third ivorybills’ nest”. That discovery sent me back to the online archives. What I found raises some interesting questions about the Singer Tract, the population density of ivorybills, at least around John’s Bayou in 1935, and about habitat quality in general.

Most ivorybill aficionados are familiar with images from the Singer Tract. I think most of us know the ones that show dramatic, ‘primeval’ forest, but I suspect we are all prone to overlooking those showing less impressive habitat (just as I am prone to taking photographs of the biggest trees and the most dramatically mature forest), even if we are familiar with the debate about how much actual old growth existed in the Tract in the 1930s. In browsing through the Louisiana Digital Library, I came across an image that I had missed, one of the bridge over John’s Bayou taken in 1940. Tanner (p.32) includes an ivorybill sighting from this immediate vicinity, just northwest of the bridge. What I find interesting about this photograph is that the forest along the road appears to be fairly even-aged and does not have the characteristics typically associated with old growth. It is similar to what can be found in many parts of Louisiana today. An image from along Sharkey Road taken in 1937 shows similar characteristics, although a 1939 shot shows more mature looking habitat and was probably taken to the east of the others.

What makes this even more interesting is that the “Third ivorybills’ nest” appears to have been found to the south of Sharkey Road in an area that was either outside or on the very edge of what Tanner considered to be one of the “Best areas for Ivory-bills” (p. 91). This map shows the location of the nest tree, which is designated “Tree III Squirrel”. (also mentioned in Bales p. 45, “two miles to the south of the first nest” and fifty feet up p. 45.) The image of the snag itself suggests  it might have been outside of prime habitat, since the cavity was 45′ (caption), 47′ 8″ (Tanner) or 50′ (Bales) up, and the snag is considerably taller than the surrounding trees.

On Edit: The oak snag could have been a super-dominant tree, which would account for the height difference and be consistent with the location being in mature forest. It’s also possible that the tree was an older tree that had been left behind. A close look at the two maps suggests it was outside the area Tanner designated as prime in 1941; it is approximately a half-mile from the John’s Bayou bridge.

On further Edit: Some of my interpretations discussed in this post have proven to be incorrect. Go here and here for clarification.

Things grow even more puzzling since what appears to be the “Elm Rock” nest, the famous one, is listed as “Nest II” on the 1935 map, and there is no “Nest I” (Nest I was near Mack’s Bayou. See following post for correction.) There is also a “Nest IV” shown. This is somewhat closer to the “Elm Rock” nest and about 2/3 of the way toward Methiglum Bayou.

In his monograph, Tanner apparently recognized nests II and III but not nest IV, and why there is no reference to a nest I remains a mystery. It seems that 1935 was a bad year for ivorybills, and there’s nothing to suggest that any of these three or four nests succeeded. It’s possible that there never was a “Nest I” and that Tanner later decided that “Nest IV” was not a nest after all. Nevertheless, it appears that at least two pairs of ivorybills attempted to nest in the John’s Bayou area in 1935 and that one of those nests was in or near the border of what Tanner would have deemed to be inferior habitat.

This raises many questions and may have some implications in terms of how the IBWO might have been able to persist. At the very least, it calls into question Tanner’s estimate that “six and a quarter square miles” per pair is “probably close to the maximum density.”