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”.
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.
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.
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.
Here are some of the fresh chips I collected, shown with my 13″ MacBook Air for scale.
Again, 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.
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.
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.
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.
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.
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.
We’ll be targeting these and will be looking for two more when I return in March.
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.
- 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.
- 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.
- 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.
- 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.
- 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.
My friend and collaborator since 2008. We came from different worlds, brought together and bonded by our passion for the ivorybill and the swamps. I will miss him.
Here’s one more from Phil Vanbergen.
Two weeks ago, Frank went into the hospital. About two days after admission, he was taken to the ICU with a systemic infection. He started showing signs of improvement on Monday this week and was able to go off the ventilator as of yesterday. (I was there from Tuesday 1/24-Tuesday 1/31.) I know Frank to be a fighter, but even so, he’s doing far better than I expected. His family is asking for prayers, so if that’s something you do, it would be appreciated. My thoughts are with him and with them.
I’ve created a page that expands on this post and should provide a good introduction to our thinking about the three most intriguing types of feeding sign, with images from the second and third categories. Think of this post as the shorter version.
Over the years, I have written a great deal about bark scaling and the types of work I think are diagnostic for Ivory-billed Woodpecker; however, I don’t feel that I’ve been effective enough at conveying the nuances of what I look for in situ. I’m going to try a somewhat different approach using images that have been posted previously. I will be focusing on the category of bark scaling that I think is most compelling for Ivory-billed Woodpecker. I hope that the tiled mosaic layout will make it easier to get my points across.
The scaling I find most compelling for ivorybill is on hickories, mostly or all bitternut hickories (Carya cordiformis). This work represents a relatively small subset of the suspected ivorybill feeding sign we’ve found, as would be expected given that under 10% of trees in the area are hickories. It is not the type of foraging sign that Tanner emphasized, and I’m not suggesting that scaling on boles is the ivorybill’s predominant foraging strategy. I emphasize this work because it has a distinctive appearance, one that differs dramatically from presumed Pileated Woodpecker foraging sign on the same species.
The above images show presumed Pileated Woodpecker work on a recently dead bitternut hickory found last February. It seems reasonable to infer that this is Pileated work because of its extensiveness and the abundance of fresh chips at the base of the snag, suggesting the work was recent and was done by a large woodpecker. Some readers might be inclined to think of this as “scaling”, when in fact it is shallow excavation. The small size of the chips and the fact that some of the chips are sapwood, not bark, support this idea. Contrast the roughened appearance of the sapwood with the clean bark removal in the images below. Also contrast the extensiveness; while the work shown above involves fairly large areas, it pales in comparison to the very extensive scaling shown below.
Edited to add: I think squirrels can also be ruled out for this work due to the involvement of the sapwood, apparent bill marks, and the presence of insect tunnels.
I think that all of the images immediately above show Ivory-billed Woodpecker work, most of it fresh. The similarity in general appearance from tree to tree should be self-evident. This type of scaling can be found from within approximately one foot off the ground to the upper parts of boles. Large Cerambycid exit tunnels are visible in the sapwood. Bark chips, when found, were large, and the only hints of excavation involved targeted digging to expand the exit tunnels. It’s worth noting that the Hairy Woodpecker in the trail cam photo above spent several minutes removing a quarter-sized piece of bark. The Pileated Woodpecker also spent several minutes on the tree; it pecked and gleaned and looked around but did no excavating or scaling.
Bitternut hickory wood is “hard and durable” and the bark is hard and “much tighter than on most other hickories.” The bark is sometimes described as being thin, but this appears to apply to young trees only. On mature boles, it can be .5″ thick or more.
Due to these qualities, the decay process for hickory snags is often more gradual than for other species, especially in higher and dryer areas. This means that the wood can stay hard and the bark remain tight for as long as three years; such is the case with the tree shown in the penultimate image above. This has enabled me to do periodic checks on some of the snags, and in most instances, they have shown little or no indication of further woodpecker work for extended periods, until the wood starts to soften and excavation becomes easier. Whatever is doing this work seems to be hitting the trees once or twice without returning or, less frequently, to be making visits several months apart. I think this suggests a thinly distributed, wide-ranging species as the culprit, and in my experience, Pileated Woodpeckers tend to return to feeding trees on a regular basis.
In my view, this very specific type of work is diagnostic for ivorybill and is beyond the physical capacity of the Pileated Woodpecker. I’d suggest that similar appearing work on other tree species should be considered strongly suggestive. When it comes to the high branch work that Tanner emphasized, it is more difficult to rule out Pileated Woodpecker. As discussed in several recent posts, this type of foraging was the predominant one during breeding season and immediately after fledging young, at least for the John’s Bayou family group. Thus, for work higher on trees, where bark is thinner and tightness cannot be assessed, abundance is likely a key indicator. From this perspective, it may be significant that our friends the Carlisles who are searching in the Pascagoula area have found only two sweet gums with work that I consider to be intriguing and consistent with what’s described in the literature. By contrast, I found over 50 such trees in our area in the 2015-2016 season alone. Whether or not there are ivorybills in the Pascagoula, the difference between the Carlisles’ observations and ours is dramatic and suggests that something unusual is going on in the Project Coyote search area.
This was an eventful trip, with an extraordinary amount of activity on the first four days – including a possible sighting and several possible auditory encounters – and none at all on the last two. I was alone on October 13th, 17th, and 18th; Frank joined me from the 14th-16th. Conditions were generally good – light winds (strongest gust, 20 MPH, was on the 13th) and sunny or partly cloudy skies. Daytime highs were in the upper 80s-low 90s, with uncomfortably high humidity on 17th and 18th. Notwithstanding the recent flooding in Louisiana, the forest floor was dry and water levels were lower than I’ve ever seen, making it much easier to reach less accessible areas.
I found very little fresh scaling, although a tree on which we had a trail cam appeared to have been worked on quite extensively sometime after my last visit in late May. The card probably contains imagery through June and possibly into July. Unfortunately, it may have been corrupted; Frank is working on retrieving the data. If I were superstitious, I’d point to this as another case of “the curse of the ivorybill”. That aside, the paucity of fresh scaling (only a few trees with small chips consistent with PIWO work at the bases) supports the idea that bark scaling has a seasonal component that is related to breeding. This is implicit in Tanner, the limited data on ivorybill stomach contents, and in several previous posts (links).
I am somewhat hesitant to mention and describe my possible sighting and some of the other possible encounters this trip but have decided that it’s better to be comprehensive and transparent. Of all the events of the past several days, I think the double knocks Frank and I heard on Saturday were the most compelling. While my views on the IBWOs persistence are unchanged, my pessimism about obtaining conclusive documentation has grown. I may have more to say about this in a future post.
And with that, here’s the day-by-day log.
I arrived in Sector 3 at sunrise on Thursday morning and got to the ‘hot zone’ as quickly as I could.
The small pond with several scaled trees, discussed in this post, was completely dry, enabling me to look at some of the downed wood that had been in or under water on previous visits. I found a large and very interesting cavity in some blowdown. Both the shape and size are unusual and more consistent with IBWO than PIWO. (My iPhone 7 Plus’s dimensions are 6.23”x3.07”)
I went a little farther south to the trail cam and noted that one of the target trees had been more extensively scaled since my last visit in May. The work is on the bole of this less than 1’ DBH sweet gum that had been damaged by a falling limb and has recently succumbed (photo below). There were large chips on the ground, but they did not appear to be fresh. If the scaling was done in June, as I suspect, we hope to have captured the source.
I hunkered down and watched the trees for some time, seeing and hearing nothing of interest. When the sun was above the tree line, I ventured south and east, thinking I’d take advantage of the low water and explore some unvisited areas.
I had a possible sighting at about 9:25. I was walking south and turned to my right, looking across a clearing to a large snag that I estimated to be approximately 200 yards away (paced off at over 170 steps and later rangefindered at 160 yards). The snag in question is very close to where Frank had a sighting in March.
I texted my wife with a description that I fleshed out in an email that evening, bracketed remarks have been added for clarification.
“I saw a brilliant flash of white as a woodpecker flew up onto the tree [this was a dorsal view.] I reached for my binoculars not my camera; I think because the distance was so great. I got the bins on the bird and got them focused as it took off. I didn’t get anything like a good look, but again saw brilliant white wings with a little black. I also had the distinct impression that the bird was much too large to be a RHWO. But it was a fleeting glimpse (or better two fleeting glimpses).
I did some playback of PIWO and IBWO and had no responses.
I . . . went to the snag. There is a RHWO roost at the very top, and I saw one juvenile and another RHWO but didn’t see the head [and could not determine whether it was a juvenile or an adult]. Though RHWOs were present, seeing them at this close range made me feel even more strongly that the bird I spotted was much bigger. I can’t fully rule out RHWO, but I also find it hard to imagine that I would have been able to get any details at all such a distance unless the bird was large.” Snag where I had the possible sighting. The bird landed on and took off from the stub at center. A Red-headed Woodpecker cavity is at the top of the left stub. My view was dorsal and from below, so the white was clearly on the trailing edges of the wings, ruling out Pileated.
This was my first possible sighting in almost three years. I was disoriented and shaken by it, as I have been with my handful of other possibles. And since it was not a good look, I can’t help but doubt myself.
In reply to my emailed description, Bob Ford had this to say:
“My ‘for what it’s worth’, I had a similar sighting once and paced it off to the same distance, then found Red-headed Woodpeckers and watched them at around that distance (maybe a little closer). Yes, can’t rule out red-headed but they look pretty small at that distance.”
As it turned out, Frank and I were able to spend some time observing Red-headed Woodpeckers in an open area at 50-100 yards. This was on Sunday morning at approximately the same time and under lighting conditions that were, if anything, somewhat brighter than those on Thursday. These observations led me to lean somewhat more strongly toward Ivory-billed Woodpecker. While the white rump of the Red-headed was easily visible at these distances, the white on the wings at a similar angle of view appears a lot less extensive and vivid than what I saw, and Red-headeds indeed look quite small.
I was able to capture a female Pileated and a sub-adult Red-headed in several frames. I’ve included a couple of the images here, both because they illustrate the size differential and because the posture of the Pileated is very similar to the posture of the bird in one of our old trail cam photos; the angle of view is different; nevertheless, it seems relevant with regard to neck length. The snag was less than fifty yards away. The first photo in the series shows the entire area. Frank measured the distance to the distant snag at right as 100 yards; the snag in the second and third images is at the left edge of the frame in the first.
On Friday morning, Frank and I had hoped to return to the ‘hot zone’, but when we arrived another vehicle was parked at the end of the road, presumably a squirrel hunter. To avoid contact with others, we went to Sector 2 but found another vehicle parked where we were hoping to hike in. We opted to hike into Sector 3 from the south, a part of the area that we visit less frequently and that’s harder to traverse when water levels are high.
I did not note the time, but I’d estimate that it was between 9:00 and 10:00. Frank did a series of double knocks, and shortly afterwards, I heard two single knocks (Frank heard one) and then a possible distant double knock that we both heard. Later on, farther north and closer to the ‘hot zone’, he did another series, and there was a loud, close single knock, followed by what may be the longest and most agitated-sounding Pileated calling I’ve ever heard. We both found these knocks somewhat intriguing, but neither one of us thought they were compelling.
On Saturday, there were no vehicles at the trailhead, so we were able to return to the ‘hot zone’. At a little after 9:00 am, we were approaching the northernmost edge when we heard 5 double knocks from two sources to the west of us. I estimated the distance at over 200 yards, but Frank put it somewhat closer, perhaps 150. We both agreed they sounded very good for Campephilus; Frank thinks some of the best ever; he wrote: “. . . three of the first five, early on, were very crisp, clean, and woody; among the best I’ve heard.”
We stopped and waited, and heard nothing. Frank did an ADK series and got no response. About fifteen minutes later, I did another series, and this time, I heard 2-4 more double knocks. Frank was applying insect repellant, the reason for my uncertainty about the number of knocks I heard. He only heard one. We sat for another 20 minutes or so, and, after hearing nothing, proceeded south to the scaling concentration. When we reached the pond with the downed cavity, we heard another DK from the south, at fairly close range.
From there, I took Frank to where I was standing when I had the possible sighting, and he measured the distance. We then went on to explore some previously unvisited places, finding some possible cavities and starts and a little bit of older feeding sign. This part of our search area is difficult to reach and navigate unless conditions are extremely dry, and we suspect it may be where roosts are located at present. If we can visit and explore it when leaves are down, we will be able to do a more intensive search for potential roosts. This is a difficult undertaking, especially given that the big trees are more than 100’ tall.
On Sunday, we went to Sector 2, the easily accessible part of which has seen a major increase in human activity and four-wheeler use over the last three years. This is the area where the tree on the homepage is located. Because waters were so low were able to get to parts of this sector that we haven’t visited in a couple of seasons due to changes in hydrology caused by beavers and and human traffic.
I was sad to discover that what I called the kissing trees, my favorites, have separated.
At 11:30, about 4 miles in, Frank nearly stepped on this canebrake rattler, only the third one I’ve ever seen.
A few minutes later, a series of approximately a dozen calls from two or three sources caught our ears. We agreed on the following details: they sounded more like “yips” than “kents” (I didn’t consciously remember that Allen and Kellogg described some ivorybill calls as “yips”); they were all single notes with no variations in pitch, perhaps not as rich sounding and higher pitched than the Singer Tract recordings, but with something of their toy horn quality; the first calls came from the east and northeast, and with movement northwestward and away from us. A Downy Woodpecker called shortly afterwards; I mentioned to Frank (and he agreed) that the “yips” had a similar quality to the Downy’s “Pik”, what I’d describe in retrospect as their brevity and emphasis.
After the calls subsided, we proceeded north for another hour or so, before looping south and west. At approximately 2 PM and at about the same latititude, I heard three more calls that were more kent-like. Frank missed them; while I suspect they came from Blue Jays, I’m including them for the sake of completeness.
On the 17th, I explored parts of Sector 1 I haven’t visited before but did not see or hear anything suggestive of ivorybills. The same was true on the 18th, when I returned to the ‘hot zone’.
I don’t anticipate returning to Louisiana until sometime in December but may do another post or two between now and then.