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Bits ‘n’ Pieces Part 1 – Louisiana Conservationist, Matt’s Take on the March Calls, and More

I had planned on writing just one more post before my next trip to the search area, but based on a small but important new development, I’ve decided to divide it into two parts. Part 2 will follow within a week or so. It will focus on the historic range both pre- and post-contact, beavers, and some further thoughts on how the ivorybill might have survived.

First, a small news item from the search area: last month Tommy Michot and Phil Vanbergen visited to check on the trail cams. One of the deployments (two cams) was inaccessible due to high water; unless flooding was extraordinary, the cameras themselves should be okay. Phil and Tom were able to reach the other two locations without difficulty. The target trees were untouched, and there was sufficient battery and card-life to keep the cameras operational until my next trip. They did not see or hear anything suggestive of ivorybill during their visit. I appreciate their braving the August heat and taking the time to get to the area.

I’ve been reviewing copies of Louisiana Conservationist (formerly Louisiana Conservation Review), the official publication of the Louisiana Department of Wildlife and Fisheries (formerly the Department of Conservation). Copies of the magazine, which is in the public domain, can be found in the Louisiana Digital Library. In the course of my research, I found one real gem and a couple of interesting pieces of less significance.

The gem is the initial report on the 1932 Singer Tract rediscovery and T. Gilbert Pearson’s visit to the area. Pearson was the first professional ornithologist to observe the Singer Tract birds. I’ve written previously about Pearson’s visit and have referenced newspaper accounts of his observations. At the time, I was focused on feeding sign and the statement about feeding on rotting stumps. As a result, I overlooked the important fact that Pearson had been searching for ivorybills to no avail since 1891; this highlights the difficulty in finding ivorybills, even during the era of relentless collecting.

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The Ivory-Billed Woodpecker: Rare Bird Considered Extinct – Found in Louisiana, Margaret A. Coogan, July 1932, Louisiana Conservation Review

The newspaper articles were somewhat less detailed than Coogan’s account, which includes some interesting tidbits. It seems likely that Pearson himself provided the information to Coogan, either directly or via Armand Daspit. There’s an inaccuracy; the mention of carpenter ants as prey is not supported by the literature.* The only record of nesting in pines is in Thompson (1885), a record that Tanner deemed “questionable”.

Somewhat more interesting is the observation, “Occasionally it feeds on the ground like a Flicker”.  In 1937, Allen and Kellogg would publish a paper describing their 1924 observation of a female ivorybill foraging on the ground and “hopping like a Flicker”. It’s possible that Pearson was aware of this observation, and the reference to scaling the bark of dead pines suggests this is so. (There were no pines in the Singer Tract.) At the same time it’s also possible that Pearson observed the Singer Tract birds foraging on the ground or described foraging behavior based on general knowledge of how ivorybills in Florida, where he grew up, typically fed.

More significant and relevant to the recordings Matt Courtman and Phil made in March of this year is the description of ivorybill calls and the pattern of calling observed. I didn’t pay much attention to the description, but Matt, who was present during the extended period of calling on March 15 was struck by it. For Matt, the correction of Audubon was significant, and as he posted on Facebook: “Please note the description of the calls being from “one to fifty” over a few minutes. This matches perfectly what we recorded in March. Very exciting!!!” Matt’s strongest doubts about the calls had to do with cadence and the lack of calls in groups of three.

Matt elaborated in an email this morning. I asked him to allow me to post it in full, and he graciously agreed. His perspective sheds additional light on the March recordings, among other ivorybill related matters. It’s worth reading.

The following explanation might be excessive, but an appreciation of my history with the ivorybill is necessary to understand the visceral response that I had to reading the 1932 article reproduced by Mark.
 
My love of nature generally, and of birds in particular, was cemented by a visit to the LSU Museum of Natural History when I was eight. In reading George Lowery’s Louisiana Birds, I was beguiled by his account of having seen ivorybills in the Singer Tract (Madison Parish, near Tallulah) on Christmas morning, 1933. In a letter that I wrote to Dr. Lowery (adorned with my drawing of a pair of IBWO), I asked him if he thought that any ivorybills still existed. He promptly replied that he sure hoped that they did. I can’t be certain about all of the contents of a letter from almost 50 years ago, but I THINK that he expressed a belief that, due to the relative inaccessibility of the ivorybill’s putative environment, that isolated pockets of ivorybills could have survived undetected for decades.
 
In his reply, Dr. Lowery offered to show me the ivorybills in the LSU collection. The very next week, my father and I went to Baton Rouge for the LSU-Mississippi State football game. In an act typical of his unfailing grace and generosity, Dr. Lowery waded through post-game traffic to open up the Museum at 10:30 p.m. just for us. Holding ACTUAL ivorybills in my hands, set me on the vacillating belief/disbelief course that I still follow five decades later. Based on recent developments, my current course is trending overwhelmingly toward the shores of belief.
 
Dr. Lowery’s national preeminence as an ornithologist was impressive: under his direction, LSU was responsible for the discovery of more new bird species than any other institution during Lowery’s tenure; during this period, an entirely new GENUS of owl was discovered by LSU in Peru and named in Dr. Lowery’s honor. Despite that, his relative optimism about the ivorybill was not shared by ANY serious Louisiana birders that I knew. In fact, other ornithology professors around the state would scoff at Lowery’s optimism behind his back. This all came to a head when, in 1971, Dr. Lowery announced that he believed that photographs (subsequently revealed to have come from Mr. Fielding Lewis) sent to him depicted a LIVING ivorybill. Whispered skepticism gave way to thinly-veiled ridicule: everyone whom I knew to have an opinion on the matter voiced their belief that Dr, Lowery was a gullible victim of an obvious hoax. 
 
At the October, 1971 meeting of the Louisiana Ornithological Society, two (inebriated…birding WAS a different culture back then:)) men tried to coax me into asking Dr. Lowery exactly where the photographs had been taken.  They figured that since Dr. Lowery and I were close, and, since I was only 10 years-old, that he might tell me. Though young, I wasn’t stupid. I declined.
 
In sum, although I wanted to believe Dr. Lowery, the birders with whom I was in constant contact with had nothing but contempt for anyone who “believed in” ivorybills. Aside from Dr. Lowery, everyone seemed to accept the Gospel According to James Tanner: after 1944, no remaining virgin bottom-land hardwood forests meant NO remaining Ivory-billed Woodpeckers. 
 
To demonstrate the sway of the Tanner Gospel, even during flickers of hope regarding IBWO, circumstances were viewed through Tanner’s lens. For instance, in 1999, as (past) President of the Louisiana Ornithological Society, I was invited to participate in a state-sponsored search of the Pearl River Wildlife Area (near Slidell) to follow-up on David Kullivan’s reported sighting of a pair of ivorybills. Having some familiarity with the specifics of Kullivan’s report, I was surprised when I saw a map of the grids that we were assigned to search. The following colloquy ensued:
           
              Matt: [pointing to a specific spot on a map] I thought that Kullivan reported the ivorybills to have been near this campground.
              State Fish & Wildlife guy: That’s right.
              Matt: Well, why are we not searching any place NEAR that campground?
              State Fish & Wildlife guy: Because Tanner’s research showed that ivorybills were found only in really big trees, and there aren’t any really big trees there.
              Matt: So you believe that Kullivan was correct in saying that he saw ivorybills, but you think that he was incorrect about WHERE he saw them?
              State Fish & Wildlife guy: [insouciant shrug]
 
Moral of the story: with the vast majority of people, historical, remote Tanner Gospel trumps actual, recent, credible observation.
 
So, for most of my life prior to 2017 I had been surrounded exclusively by Tanner-quoting ivorybill “deniers.” Despite my veneration for Dr. Lowery (who had passed away in 1978), I could not but help to have their rigid doubts shape my views regarding the existence of IBWO.  In February, 2017 my friend, Frank Wiley passed away. Along with Mark Michaels, Frank had founded “Project Coyote,” in hopes of finding and documenting ivorybills. As a tribute to Frank, I decided to visit the Project Coyote search site in Louisiana. I had zero expectations regarding the trip. In fact my dominant thought prior to the trip was: “I am going to make a concentrated effort, spend several days in the woods, observe nothing to suggest the continued existence of ivorybills, and, then, FINALLY extinguish any lingering delusions about ivorybills so that I can get on with more productive, practical uses of my time.”
 
In preparation for the trip, I began to read through all of the blog entries on Project Coyote’s website.  There, through the heroically-diligent work of Mark Michaels, I discovered something shocking: that Tanner’s own data did not support the chief tenet of the Tanner Gospel, that ivorybills were found only in virgin bottom-land trees. As with the Bible, many people quote Tanner to support a particular assertion, but few people have actually read all of Tanner’s work.
 
Back to the issue at hand (finally!): why was the 1932 statement regarding the ivorybill call so meaningful to me?  The passage in question was: “The bird’s note is a peculiar nasal ‘yank,’ NOT REPEATED THREE TIMES as Audubon states, but as many as from ONE TO FIFTY in a few minutes (emphasis supplied).” For me this was like finding the missing link. The only thing that had conjured doubts (about the sounds being from ivorybills) in me about my recording was that the notes did not come in series of threes, but rather were relatively monotonous and evenly-spaced over an extended period of time. Prior to reading this 1932 description, I had never even considered that Ivory-billed Woodpeckers would call in any way that was NOT a series of three notes.
 
My myopia had been further compounded by my frequent exposure to the only widely-accepted recording of the ivorybill. The 1935 Cornell recording definitely presents as a series of three notes. As anyone can attest who has used the Cornell recording as playback when looking for ivorybills, hearing it repeatedly primes your brain to expect a series of three notes to be the only “valid” response that would indicate the presence of an ivorybill. Mark has since informed me that the literature contains many references to “non-three” note descriptions. In fact, I probably have encountered many of those same descriptions over the years. As with Tanner-induced single-mindedness, however, I had never INTERNALIZED anything other than, “If I ever hear an Ivory-billed Woodpecker call, it will come in the form of three notes.”
 
As I was reading the 1932 passage, my wife, Lauren, could tell that I was reacting emotionally to what I was reading. For the ONLY time in our eight years of wedded bliss (actually, not hyperbole) regarding something that I was reading, she asked: “Are you OKAY?” I find my visible, somatic response to be at least as important as all the intellectual reasons that I could adduce to explain the importance of the 1932 description. 
 
In sum, that 1932 description removed whatever lingering doubt that I had maintained regarding the probable source of the sounds that I recorded on March 15, 2017. Subjectively, I am convinced that I recorded at least two (and probably three) Ivory-billed Woodpeckers that day. Objectively, I can state unequivocally that the calls were consistent with those to be expected from ivorybills. While acoustics alone will never be sufficient to establish the continued existence of the ivorybill, for me the only pertinent question that remains regarding the 3/15/17 recording is: “Could anything other than an ivorybill also account for those sounds”?
 
Congratulations on reading my tome in its entirety! Please feel free to share with anyone. Of course, I would be happy to answer any questions raised herein.

The other interesting tidbits from Louisiana Conservationist pertain to possible ivorybill sightings in the 1950s. Both items (letters from readers and responses from state officials) are certainly questionable, but they also point to the way Pileated Woodpecker became the default, even when the description was inconsistent with PIWO.

The first is interesting for its location. Urania, Louisiana is southwest of the Singer Tract and is relatively close to the Project Coyote search areas. It was founded by Harry Hardtner in the 1890s and is considered the birthplace of conservation and reforestation in Louisiana. The image that prompted the letter is included for reference.

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The second letter is peculiar, but the description is considerably more suggestive of ivorybill than Pileated – like a Red-headed Woodpecker but the size of a chicken.

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There’s one additional tidbit that doesn’t pertain to Louisiana. In the past, I’ve wondered about record committee submissions and how many there may have been over the years. A divided Arkansas committee accepted the Big Woods report (a fact that’s often glossed over in the literature), while the Florida committee rejected the Auburn reports. Other than these submissions, I was aware of one from Texas, from out of range and in unlikely habitat. I recently ran across another, from Florida, also rejected but interesting nonetheless. Here it is, for what it’s worth:

Ivory-billed woodpecker, Campephilus principalis.
FOSRC 2011-852. This bird was described from an observation in suburban St. Augustine, St. Johns Co., on 13 April 2011. Although the observation included key characters of the Ivory-billed Woodpecker, such as a white bill and white pattern on the back while perched, the observation was at a distance of 30 m and made without binoculars. It is the Committee’s opinion that the only acceptable submissions of this species would be those with veri able evidence (e.g, identifiable photographs or video). The recent controversy over video recordings, audio recordings, and sightings in Arkansas (Sibley et al. 2006) and Florida (FOSRC #06-610, Kratter 2008) calls into question whether the species may have persisted into the twenty-first century.

More soon.

*Ants are described as a prey species in Bendire (1895), but this is based on a misreading of Thompson (1885). Allen and Kellogg (1937) mention an observation involving suspected feeding on ants but found no ants or termites when they examined the substrate. The closest thing to evidence for ants as prey involves a Cuban Ivory-billed Woodpecker with a hugely overgrown bill that was observed feeding on arboreal termites – a species not native to the continental United States. It was observed and collected by Gundlach in 1843 and was also being fed grubs by its companions. Jackson speculates that this might have been a young adult bird, but given the extent of the hypertrophy, this strikes me as being somewhat unlikely. I’ll opt for the altruistic possibility that Jackson also posits. (Jackson 2004).

 

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Go Read Bill Pulliam’s Blog While You Can

I had been planning to do a post with various ivorybill related tidbits in anticipation of the search season, which begins next month. That will be coming in a week or so, but I want to say a little more about Bill Pulliam first (beyond his Luneau video analyses, which I think should be dispositive). This decision was inspired in part by one of our advisors who pointed similarities between what Bill observed in Tennessee and what we’re seeing in Louisiana. While the physical characteristics of our old search area seem to have more in common with Moss Island, Tennessee than where we’re currently focused, Bill’s perspectives are relevant to both.

Edited to add: Moss Island is a small wildlife management area encompassing 3400 acres. I’m not sure what percentage is mature bottomland hardwood forest, but there are a variety of other habitat types. Compared to our search areas it is relatively isolated and distant from other large tracts of forest.

As an aside, Cyberthrush also has a post honoring Bill with a link to an eBird tribute.

With comments included, Bill’s series of posts on Moss Island runs to nearly 54,000 words. There’s no telling how long this series will remain readily accessible online, and indeed some of the images and sound files are no longer available. The entire series is worth reading and saving if you’re seriously interested in the ivorybill. It starts here.

On re-reading the posts for the first time in eight years, I’m struck by how much Bill influenced me without my recognizing it and/or how much the evolution of my understanding between  2009 and today is congruent with the ideas he expressed just as I was getting more deeply involved in searching.

Like Bill, I suspect that the near extirpation and revival of the beaver may be central to the ivorybill’s decline and survival (more about this in my next post). Like Bill, I think that Tanner’s model failed to account for environmental changes that had taken place in the preceding centuries. Like Bill, I think that if the ivorybill survived, it had to have adapted in ways that are inconsistent with Tanner’s a priori assumption that the species is old-growth dependent.

Bill was tough-minded and opinionated. There were times when I thought he considered me a somewhat annoying amateur. While we hadn’t communicated about it in recent years, he took a dim view of my efforts to make sense of feeding sign in the early days. Most of our correspondence took place in the 2000s, while he was still actively blogging about the ivorybill. After that, I sought his input sparingly.

My last exchange of emails with him pertained to the March recordings. Without quoting him directly, I think it’s fair to say he thought the calls were likely or more than likely Ivory-billed Woodpecker. He also thought it unlikely that birds were resident in our search area, based on the pattern of potential encounters, the paucity of strong sightings, and lack of conclusive evidence. I’m not sure I agree; I wish there had been a chance to explore this topic in more depth and that he’d been able to see our search area for himself. Nonetheless, his perspective has led me to consider that other nearby forested areas deserve more attention than we’ve given them to date.

I’ll conclude with three paragraphs from his final post in the Moss Island series. It’s as true today as it was in November 2009 (though I suspect nesting may take place in fragmented second growth, as in our old search area). I hope it inspires you to read the rest. More from me soon.

How does this relate to Moss Island? By Cornell standards, our habitat is unsuitable. Hence, our encounters are largely dismissed out of hand. By doing so, the Cornell approach has painted themselves into a rather nasty corner. The logic is simple. To all appearances, we have Campephilus-like double knocks that are at least as good as what has been heard in the “core habitat” such as Big Woods and Congaree. If one claims that in “core habitat” these represent evidence for the possible presence of Ivorybills, but in “marginal” or “unsuitable” habitat they provide no evidence for the possible presence of Ivorybills, one has committed a logical no-no of the first magnitude. If the same sounds come from places where you have concluded that Ivorybills are not going to be, then you should conclude that these sounds have no relevance to Ivorybills anywhere. Conversely, if you feel these sounds are evidence of the possible presence of Ivorybills in South Carolina or Arkansas, then you must also accept that they would be evidence of the same in Tennessee, Illinois, Mississippi, Florida, Louisiana, and Texas. You can’t have it both ways.

Anyone who seriously considers that Ivorybills might still persist, and that double knocks and other soft evidence have a relevance to indicating their possible presence, should accept that the evidence in total suggests their habitat requirements might be broader than has been assumed by Cornell et al. I’m not suggesting they will nest in fragmented second growth, or even use it as a full-time habitat; but there are ample indications that if these sort of encounters mean anything anywhere then the birds indeed are using fragmented “marginal” habitats for at least parts of their life history. These habitats are hugely more extensive than the “core” habitats, hence this possibility raises all sorts of further hypothetical possibilities for the natural history, survival, and conservation of the species, all of them positive. In the alternative philosophy to Cornell’s, you search where you have learned of rumors, whispers, or credible declarations that something of interest might have been seen or heard there. This of course requires a lot of judgement, and eventually everyone will draw the line somewhere; I’d not put much stock in reports from western Kansas, for example — although good double knocks in Nebraska or Vermont would settle a lot about what they might mean in Arkansas! But until and unless we actually find some reproducible birds and determine what their 21st Century habitat use patterns really are, minds should be kept open.

You will not get anyone involved in the Tennessee project to state that we have established the presence of an Ivory-billed Woodpecker anywhere in Tennessee as a statistical or scientific certainty. None of us has put an Ivorybill on his or her life list. However, if you asked us off the record for our own personal unscientific feelings, I think you would hear several confessions that indeed, some of us do strongly suspect that there has been at least one of these critters tormenting and taunting us in the delta woods for the last several years. Which means we also think that all that follows from this about habitat, behavior, distribution, etc. should be given serious consideration. Interconnected mosaics of fragmented second growth bottomland forest should be included within the spectrum of possible habitats for the species. You will not get anyone involved in the Tennessee project to state that we have established the presence of an Ivory-billed Woodpecker anywhere in Tennessee as a statistical or scientific certainty. None of us has put an Ivorybill on his or her life list. However, if you asked us off the record for our own personal unscientific feelings, I think you would hear several confessions that indeed, some of us do strongly suspect that there has been at least one of these critters tormenting and taunting us in the delta woods for the last several years. Which means we also think that all that follows from this about habitat, behavior, distribution, etc. should be given serious consideration. Interconnected mosaics of fragmented second growth bottomland forest should be included within the spectrum of possible habitats for the species. 

 

 

 


Possible Double Knock in Reaction to a Barred Owl

For a slight change of pace, I’m posting this possible double knock in reaction to a calling Barred Owl that Patricia Johnson captured at 8:40 AM on March 29th, within 50 yards of where the calls were recorded on March 11 and 15. I’m posting this particular double knock because the context may give it added significance – the apparent reaction to the Barred Owl call and the fact that there was no temporally proximate ambient foraging.

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I’m somewhat hesitant about posting recordings of knocks, especially those not noted in the field, for a number of reasons: our field tests have revealed that in deep woods, ADKs can sound like single knocks at a couple of hundred yards; it’s also not uncommon for observers to disagree about whether knocks heard in the field are singles or doubles, and the same is sometimes true about recordings. In addition, most of the interesting knocks captured last month are faint on the sonograms, and in the case of the knock posted below, the second knock does not show.

Nevertheless, this double knock appears to be in the right range for Campephilus in terms of the interval and the pattern – louder first knock followed by a softer second one.

Edited to add: Another reviewer has suggested that the knocks are “too slow”.

I’m two trip reports behind and hope to get to them before returning to Louisiana.


Hickory Scaling

Yesterday, Phil Vanbergen visited the search area and found fresh scaling of the kind I think is diagnostic for Ivory-billed Woodpecker on a hickory. This is an exciting development because we found no fresh work of this type last season.

While Phil was unable to get to the base of the tree to examine the bark chips, the scaling has the distinctive appearance, including abundant insect tunnels, discussed in multiple posts and on this page. While the video doesn’t show the detail that still photographs can, I think it conveys the extensiveness of the work more effectively than stills.

Edited to add: Phil found this striking clip of a foraging Crimson-crested Woodpecker (Campephilus melanoleucos). The similar appearance of the feeding sign should be apparent.

Update: Phil shot a second sequence from a different angle, and Steve Pagans has slowed it and edited it into two shorter clips. In the first, the edited version shows the scaled surface more clearly. The presence of buds in the second suggests that the tree is still alive, though probably just barely. If you listen to Phil (sounding like a death metal singer or, as he put it, Megatron from Transformers), you’ll hear him mention thinking of a lightning strike. Steve Pagans also noted the similarity. If there was a strike, it wasn’t recent, although it’s possible that a strike some years ago wounded the tree, setting the stage for a Cerambycid infestation.

 

We’re confident that this work was done between late December and yesterday because we visited the same location in December and Phil photographed Patricia and me with a huge relict cypress; the hickory is about 50 yards away, and the work would have been obvious to us had it been there at the time.

April 4 is the earliest I’ve found recent scaling of this type, and the January or February date for this work is a surprise. But the winter has been unusually warm.

Edited to Add: After visiting the tree and another one nearby, I’m retracting the above. I doubt that the initial scaling on these two trees was done more recently than September 0f 2016. I have also revised the title accordingly.

Phil returned yesterday and trained a camera on this hickory. I’ve never seen signs of a return visit to such an extensively scaled tree, and image quality may be an issue because conditions required placing the camera farther away than we’d like. Nevertheless, we had to give it a try.

I’ve written an in-depth post on bark that is currently password protected. I’m awaiting some feedback and a copy of a paper for which I’ve only read the abstract. I plan to make it public soon.


Another Pileated Scaling Sequence – January 11, 2017

Part 1 is here. Part 2 is here. I encourage you to read those posts first, as this one only adds a little to what’s been documented and discussed. Phil Vanbergen found an additional sequence this morning, one that shows the balance of the scaling that was done on the limb between December 22nd and January 26th.

In this sequence, Pileateds do most or all of the work that I had ascribed to squirrels. As in the other two sequences, the birds spent approximately fifteen minutes foraging, removing a couple of small patches from the lower part of the limb before working somewhat more extensively on the upper left. As in the other sequences, it appears that one bird did the vast majority of the work, but I haven’t found any frames that are well enough resolved to determine whether it was the female or the male. Per Phil, squirrels can be seen in additional sequences, “often poking around the scaled patches”.

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Pileated Woodpecker Scaling on the Limb of a Downed Sweet Gum – Part 2

Thanks again to all who sent condolences, and appreciations of Frank Wiley and our work. Your sympathy and support have comforted and encouraged me during this difficult time.

Part 1 is here. This post supplements the analysis at: Feeding Sign: Some Possible Ivorybill Diagnostics. I’ll be reiterating ideas that are familiar to longtime readers; I have posted many of the photographs before; but there’s some additional research and some new perspectives informed by the Pileated scaling sequences obtained in December and January.

I am now firmly convinced that the work we’ve found on a small number of hickories over the past several years cannot have been done by Pileated Woodpeckers. I have believed this to be the case for some time, but the recent sequences showing how Pileateds scale sweet gum bark provide strong, direct evidence in support of that conviction.

As noted in Part 1, sweet gum bark is in the mid-range for tightness among hardwood species. Hickory bark in general, and bitternut hickory bark in particular, is at the highest end of the range in terms of adhesion. Hickories belong to the genus Carya, which is divided into two types, “true” and “pecan” hickories. Bitternuts are in the pecan group, “which are not equal to true hickories in strength, hardness, and toughness.” This inequality is relative, and the differences are modest. In addition, the timber industry identifies bitternuts and a true hickory species, mockernuts, as “tight barked” hickories. True hickory bark adheres so tightly that its removal poses problems for the pulp lumber industry, and I suspect that for the purposes of the linked study, bitternuts are treated as true hickories. In any case, it is safe to say that hickories are the tightest barked hardwood species in our search area, and I have observed that hickory bark can remain tight for years after death, given the right conditions.

Now let’s examine the physical evidence we’ve found with regard to both sweet gums and hickories.

These are three of the largest chips found under the medium-sized limb of the downed sweet gum. There was one larger chip that broke on handling, as well as quite a few smaller ones. This is known Pileated Woodpecker work.

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It is perhaps more accurate to describe these as strips. They’re approximately .25″ thick and 2″ across at the widest points.

Now let’s look at some presumed Pileated Woodpecker work from another sweet gum that appears to have been longer dead. This work is from somewhat larger limbs and a nearby hanging broken limb. I can see indications, patchiness and layered appearance, that would lead me to suspect Pileated, just based on the field impression. The chips are even more revealing, even though some of them are larger than what I would have expected.

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Here’s an image of the chips found on the ground. There’s been a lot of scaling on this tree, and some older chips (that could be consistent with ivorybill) can be seen in the photograph. Note the variability in size.

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Here are some of the fresh chips I collected, shown with my 13″ MacBook Air for scale.

img_1260Again, some of these chips are slightly larger than I would have hypothesized for Pileated Woodpecker, but the appearance, which suggests that a considerable amount of pecking was required before the bark was removed, would have led me to assume Pileated. I’m confident this is not squirrel work either, based on the exit tunnels and the way they’ve been pecked at (most readily visible at the far right). Note also that these chips were so brittle that the larger ones broke in transit. This work was done on larger limbs, and the bark is approximately .375″ thick.imgp4295

By contrast, the hickory scaling is on boles, where bark is tighter and thicker; the surface area involved is typically much greater; and there is no sign of the layered appearance, which I presume to be a consequence of pecking rather than chiseling/prying. In those instances in which we’ve found fresh work, most or all of it appears to have been done within a very short timeframe. The example below, the homepage tree, was still alive, with the scaled areas wet with sap when found.

We found this tree in the spring of 2013 and monitored it regularly for over a year. There were no return visits by whatever did the scaling, and the only other woodpecker work involved the removal small patches of bark by a Hairy Woodpecker (captured on a trail cam). This particular tree had been partially uprooted and was in a lower, wetter area than many of the other hickories that have been worked on in this manner. By the spring of 2016, it had fallen and Pileated Woodpeckers were feeding on the rotting log.

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I’ll repost the known PIWO scaling, done over approximately 30 minutes in two visits, five weeks apart, for comparison. Even if the same species of tree were involved I’d have suspected two different sources for the scaling.

As I see it, our Pileated sequences show that it would have required hours for a PIWO to have scaled so extensively on the hickory bole and suggest that they could not have done so as cleanly. The chips (>.375″ thick on a relatively young tree, not at all brittle, and no hint of pecking or removal in layers) and the remaining adhering bark should have a very different appearance if Pileateds were responsible, especially given the substantial differences between sweet gum and hickory bark adhesion and hardness. The work we’ve found on hickories involves both live and recently dead examples. Again, I’ll repost an image of the hickory chips from this tree for reference.

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Suspected Ivorybill Chips

As discussed previously, the hickory scaling also has a distinctive appearance that strongly resembles presumed Ivory-billed Woodpecker scaling on one of the Singer Tract nest trees, a maple.

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Suspected Ivorybill Scaling on Hickory 2013

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Detail of the “Elm Rock” Nest Tree, 1935, courtesy of the Division of Rare and Manuscript Collections, Cornell University

I think it may be possible to distinguish Pileated and Ivory-billed Woodpecker work on sweet gum branches, based on very close examination of the scaling and the bark chips (when possible). The effort to do so is complicated by the fact that both Pileated Woodpeckers and squirrels can and do strip bark in similar ways. Extensive, mostly contiguous, and clean appearing scaling on larger limbs may be suggestive for ivorybill, as in the example below and as Tanner suggests, but even if ivorybills are doing some of this work, identifying it requires making some fine distinctions.

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By contrast, I think the work on hickory boles in our search area is diagnostic for ivorybill. Our focus going forward will be on trying to anticipate and document whatever is scaling bark from the hickories in this distinctive manner. Given the nature of hickory bark, I suspect I will have reached a dead end if it turns out I’m wrong about this.

One final note, identifying potential target trees is a very long shot. We found no scaled hickories of this type in 2015-2016. I have been looking for candidates on the last two trips and have found two wounded trees, both within 50 yards of hickories that have been scaled in recent years.

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We’ll be targeting these and will be looking for two more when I return in March.


Pileated Woodpecker Scaling on the Limb of a Downed Sweet Gum – Part 1

I’m still in mourning and adjusting to the loss of my friend. Thanks to all who have expressed appreciation for our work and a desire for it to continue. I’m sure Frank would have felt the same, and with that in mind, this will be the first of two or three installments discussing Pileated Woodpecker work on sweet gums that we’ve recently documented.

After my December trip, Phil Vanbergen and John Williams retrieved the trail cam we had deployed on December 21. They took the camera to Frank’s house, reviewed the card, and found that two Pileateds had visited the downed tree on the 22nd and had scaled some bark near the base of a medium to large limb. Phil, who has spent time with me in the field and who has paid close attention to my approach to analyzing feeding sign, immediately suspected Pileated for this work, based on the appearance of the scaling and the characteristics of the bark chips.

Rather than extract the images at that time, Frank and Phil opted to redeploy the camera. Although I had not yet seen the frames, many of my last communications with Frank, both on the phone and via email, touched on this subject. He was tickled by the fact that we’d anticipated and documented scaling activity on an untouched limb and was eager to get back out and see for himself. Sadly, that was not to be.

Phil and I retrieved the trail camera on January 28. I had visited the site on the 26th and had noted some additional scaling consistent with what I’d expect for Pileated Woodpecker, although with some bark chips on the larger side. As it happened, the second round of scaling had taken place approximately three hours earlier, five weeks to the day after the first.

In both instances, it appears that almost all the scaling was done by a female, although the image quality is too poor for me to be 100% certain. In both cases, the bird spent approximately 15 minutes on the trunk. It seems that squirrels (seen briefly at the beginning of the January series) are responsible for the modest quantity of scaling on the upper, less vertically oriented, part of the limb; this was my instinct at the time, and the idea is supported by the footage. The full time lapse sequences are at the bottom of the page. Phil extracted both sequences, and Steve Pagans created a slower version of the January 26th clip. The first four photos in the tiled mosaic series below were taken by Phil Vanbergen.

I’ll go into more detail in subsequent posts, but for now, I have a few observations.

  1. This work has a distinctive appearance, what I’ve called a layered look to the edges, that is consistent with what I’ve previously hypothesized for Pileated.
  2. While some of the bark chips are on the large side for what I have ascribed to Pileated, none are anywhere near as large as the larger ones that that we’ve ascribed to ivorybill. In addition, the chips found at this location and at another where I suspect the source is PIWO, seem to be less uniformly large in size and sometimes show signs of being taken off in layers, which matches what’s visible on the limbs.
  3. The tree in question was no more than six months dead, and the bark at the edges of the scaled area remained tight; however, dormant sweet gum bark is in the midrange of tightness relative to other hardwood species.
  4. This is a decay class that Tanner associated with ivorybills not PIWOs, but it’s clear that Pileateds can and do scale very recently dead sweet gum limbs, at least in mature bottomland forests.
  5. Tanner’s photographs provide little guidance in terms of differentiating between Pileated and Ivory-billed Woodpecker work on high branches. I suspect he thought of his monograph as more epitaph than guide to identifying feeding sign. Nevertheless, his descriptions offer some clues. “Scaling, the Ivory-bill works steadily, removing all the bark for quite an area; one may work at a spot for an hour or more.” And for Pileateds, “What scaling Pileateds were observed to do was mostly on loose bark and was never as extensive or as cleanly done as the work of the ivorybills.

To conclude this installment, we already suspected that Pileateds can and do scale freshly dead sweet gums before the bark has loosened; these images show them doing it in a way that is inefficient and neither ‘extensive’ nor ‘clean’. The total surface area scaled over approximately 30 minutes is modest compared to scaling we suspect to have been done by ivorybills. In addition, PIWO work has some characteristics that may be recognizable upon close examination of the affected limbs and bark chips. The fact that these characteristics can be seen on medium-sized sweet gum limbs, with their relatively thin and only moderately tight bark, suggests that it should be even more evident on larger limbs, boles, and other tighter barked species. More on this and on bark chips in subsequent posts.