Since we’re now involved in a formal scientific study, I will refrain from posting about possible encounters until the end of the season. Similarly, we will refrain from using attraction methods (playbacks, kent-imitations, ADKs) while the study is ongoing. We will have a steady presence in the area but will endeavor to tread lightly.
The work on deploying the AudioMoth units began on the evening of Thursday, February 7, with an instructional session led by Tessa Rhinehart of the Kitzes Lab. In the course of this session, we decided on protocols for the deployment period to insure that there’s no confusion about the data collected.
The next morning was training day. We set out to do our first round of deployments, with rotating groups of two learning the process. I was a little unnerved when it took us most of the day to hit eight deployment points. Fortunately, the pace picked up considerably over the course of the week.
On Saturday we broke up into teams of two. A journalist joined Steve Latta and me to observe and record the deployment process. This is someone who had interviewed Frank and me and spent time in the field with us a few years ago. News of the ARU deployment renewed his interest in the story, and if all goes well his report will be airing soon. Stay tuned.
Thanks to Tessa Rhinehart – for her clear instructions, for wrangling us all, for braving the challenging conditions. Thanks also to Steve Latta, Matt Courtman, Mike Weeks, Tommy Michot, Phil Vanbergen, and Patricia Johnson for all their efforts. We covered a lot of ground and worked hard to get the job done by mid-day Wednesday. Deployments are effectively completed for the season, with units to be swapped out for review. We have opted not to spread the recording units as thinly as we had originally planned.
I had one especially interesting find, a form of foraging sign I have only seen once before, in a cluster in 2015. It’s unusual, distinctive, and though it’s somewhat outside the category I’ve suggested may be diagnostic, I think it’s likely ivorybill work and have some hope we’ll be able to resolve that question once and for all.
I found a sweet gum limb standing, embedded in the ground. It had fallen recently, as dead leaves and balls were attached; the bark was very tight; and the wood was hard, showing no signs of rot. I found a small cluster of similar work in 2015 (scroll down in both linked posts), but this type of of feeding sign is extremely unusual for the area, and I’ve never seen it anywhere else.
In 2015, I was able to identify an invasive ambrosia beetle (a tiny Scolytid) as the source of the infestation. Sweet gum is one of the main host species, and infestation, which can kill limbs and saplings but not larger trees, has become increasingly common
The chunks of bark on the ground included the largest ones I’ve ever seen from a sweet gum, the one Steve is holding below, in particular. We have documented Pileateds removing bark from sweet gums, but never in pieces approaching this size or as extensively when bark is thick and tight. While this type of work is somewhat different from what I’ve hypothesized may be diagnostic for ivorybill, I suspect that IBWO is responsible for it. We’re hoping to be able to test the samples Steve collected for DNA, so stay tuned for that.
The only close-up of ivorybill excavation is in Tanner’s dissertation, showing some small holes in a hackberry. I see a similarity between that work and some of these digs.
I found one especially intriguing older cavity in a sweet gum snag this trip. The shape is unusual; it seems to be an expanded knothole. The same appears to have been true of the 1935 nest cavity. The fact that this cavity is surrounded by a scaled area makes it especially interesting, though it may well be disused.
Brief Update on Another Area
Before meeting up with the team on February 7th, I spent the morning of the 6th in the vicinity of the Saucier sighting. It seemed a fitting way to remember Frank, a year and a day after his passing. As has been the case in a number of prior visits, large cavities and bark scaling are easy to find, though the scaling was not as suggestive as the best examples from our main search area.
I’m planning another post related to trail cam deployments before long.
Exciting news on the search front, and we’re indebted to Matt Courtman for making this happen. It is a dream come true for me, and I hope it will represent a major breakthrough in the search effort.
This post is going live on the second anniversary of Frank Wiley’s passing. I imagine that he would be as thrilled as I am about this new development.
Matt recently reached out to the National Aviary, which is collaborating with the Kitzes Lab at the University of Pittsburgh on a variety of acoustic monitoring studies. As a result of Matt’s efforts, Pitt and the Aviary will be supplying us with 200 remote recording units, as well as technical support and processing of the data collected.
The technology has advanced considerably since the organized ivorybill searches in the early 2000s.
We plan to start deploying the units toward the end of the week, with the hope that we’ll be able to home in on potential nest/roost sites in our primary search area. Barring that, we hope the data collected will at minimum provide insight into the movements of putative ivorybills in the area. In addition, we’ll be deploying units in a number of other Louisiana locations.
In other acoustical news, Guy Luneau, whose acute hearing and outstanding ear-birding ability continue to impress, listened to the compilation clip discussed in the previous post and heard something that, to the best of my knowledge, everyone had missed. I know I had.
There are two calls toward the end of that clip (at around 2:25) that sound very similar to the “wonka-wonkas” or “wonks” (as Guy calls them to make it clear the sounds are single syllables) calls from the ’35 recordings. They’re soft, the first softer than the second, but they can be heard on headphones and both show up on the sonogram, the first very faintly. They occur approximately 3 seconds into this 16 second clip.
I’ve extracted a relevant segment and created a sonogram using Sonic Visualizer. I have also included a bit of a sonogram from the Singer Tract showing both kents and wonka-wonkas. (The relevant segments can be found at 0:57 and 3:14 on the Allen and Kellogg recordings.) Note the smaller harmonic interval (distance between each horizontal line) in the wonkas as compared to the kents. Also note that the wonkas frequently came in pairs, with the first note considerably shorter than the second.
The two calls are at the left of the screen cap. The similar harmonic structure suggests to me that the source is the same creature. I think it also tends to further support the suggestion that these calls were made by ivorybills and tends to exclude other species.
I had reason to listen to this clip yesterday and realized that I’ve not previously posted it. It includes amplified selections, greatest hits, from the March 2017 recordings – numerous calls and some knocks, including several in apparent response to Matt’s banging with wooden blocks. At this point, I’m not even sure who made it, probably Steve Pagans. In any case, it’s worth a listen, especially if you haven’t heard the recordings before. Headphones aren’t a must, but they’ll help.
The calls are not a perfect match for the known ivorybill sounds recorded in the Singer Tract, but they are similar in many ways. They are also consistent with historical descriptions of ivorybill calls. They do not seem to match any known North American animal. The fact that the suggestive calls and knocks occurred during the same event lends further weight to the idea that Ivory-billed Woodpeckers are the source of the sounds (which seemed to come from more than one source).
Similar sounds are heard rarely in the area, and we have recorded some. The events of mid-March were unique, however, in that the calls were heard in the same location on multiple days, and on the morning of March 15, they continued for hours and numbered in the hundreds. Since that time Matt recorded three calls in April 2018 and Guy, Jay, and I heard similar sounds on New Year’s Day this year.
We are gearing up for a more intensive search effort as the season heads toward its peak. More about that in upcoming reports, so stay tuned.
This trip had its ups and downs, including a couple of possible encounters on New Year’s day (discussed below). Weather and accompanying high water posed major problems. Flooding was unprecedented in my experience, and much of the core search area was inaccessible. With three inches of rain predicted for my last two field days, I cut my stay short and went to New Orleans to avoid possible flooding, catch up on some work, and for a little R&R (and chaos).
There were also technical problems – trouble navigating a new camera and my recording device (a replacement for one lost in the field last trip). I’ve included a few of my own photos, though they are not up to my usual standard for posting. The vast majority are courtesy of Erik Hendrickson.
I was in the field from December 29-January 1, as was Jay Tischendorf. Erik arrived the day before and remained until January 4. We were joined by our newest team members – MW, Louisiana-based photographer, who has been doing great work surveying the area and surroundings, developing a more comprehensive picture than I have been able to manage, and Guy Luneau, who arrived on December 31 and was making his first visit to the search area. Guy is a very accomplished birder with great hearing and a deep knowledge of bird calls, especially those of the southeastern US.
It was unnerving to discover that some upland areas have been marked for logging, down to the very edge of the core search area, and within perhaps fifty yards of the location where the March 2017 recordings were made.
High water was a major obstacle. On New Year’s day, Guy and I wore chest waders, but it became apparent, within about 20 yards after leaving the uplands, that water would be over our heads in some of the sloughs. I’ve never seen conditions like this in the area. Click on an image in the gallery to see them the full-size photos.
On Saturday, December 29, Jay, Erik, MW and I tried to reach the northern group of trail cams. After entering the bottoms, crossing on the log shown above, we were able to reach the northernmost of the cameras but were unable to go more than about 100 yards beyond it. I’ve reviewed the card; there was no new woodpecker activity and a couple of very brief squirrel visits to the scaled patches. There was no observable change to those surfaces.
On the 30th, seeking higher, dryer ground, we visited an upland area in the floodplain of a small stream. This is a patch I’ve wanted to explore for some time, since our logging history map shows an entry date of 1910. As is the case in areas where pine has been cut, stumps from the pre-chainsaw era were scattered around. The forest is not terribly impressive, probably due to soil conditions. There were few dead and dying hardwoods, but we saw several patches of recently dead and debarked pines.
MW departed and Guy Luneau joined us on the morning of New Year’s Eve. We tried an alternate route to the unserviced northern cams. This required a much longer traverse of upland areas, including a large parcel marked for cutting (the blue tagging on the trees shown above is one boundary of the area to be logged). Unlike the other plot, where the larger trees are being taken, this appeared to be more of a thinning operation. It is still unnerving, and there seems to have been an uptick in logging operations in areas that I believed to be protected.
When we got to the bottomland, near the location of the March 2017 recordings, we found it completely flooded and were unable to enter, let alone get anywhere near the cameras. Although we’ve been careful to deploy cameras near head height whenever possible, I suspect that we’ve lost several, possibly as many as 6 of our 8 functioning units, to the flooding. Team members will be returning to check on the cameras within the next couple of weeks.
All the excitement took place on New Year’s Day. There had been a little break in the rain, and we hoped to reach the southern cluster of trail cameras. It soon became clear that this would be impossible. In the southern area, the bottom is considerably wider than where the other cameras are deployed. Here too, water reached the edge of the uplands, and the first slough, which can usually be crossed in ankle-high boots, was completely out of its banks, with water crotch deep approximately 20 yards from where the edge should have been. We messed around on the edges of the bottoms for a while, but found no entry points. At a little after ten, we decided to do a double knock series.
As was the case for most of the trip, woodpecker activity was lower than normal, and double knocks were less productive of responses from other species than is usually the case. As a result, I did a fairly aggressive series over a five minute period. About 15 minutes after I finished, Erik and I, who were standing and positioned somewhat closer to the sound, heard a distinct single knock – clearly a blow to a woody substrate and not an industrial sound or gunshot – at an estimated distance of 300 yards. (I said 300 yards or more; Erik said 300.) The sound was isolated and not associated with foraging knocks or other woodpecker drums. Unfortunately, I thought my recorder was running at the time, but such was not the case.
Stymied at this location, we returned to our vehicles to see if we might be able to reach the bottoms by a different route. We were able to do so, and to walk along a higher stream bank, penetrating a mile or so into the core habitat before an uncrossable slough blocked our progress. At around 1:30 pm, we were walking downstream on the bank, when Guy stopped us, having heard some interesting calls. Jay heard them next, a little less well. I was the last in our party to hear them, and they were at the very edge of my hearing.
We attempted some Blue Jay playbacks and also some playbacks of the March 2017 recordings (using an iPhone without external speaker). Neither produced a response. And we noted no Blue Jays calling at the time.
In the discussion that followed, it became clear that two sources were involved. Guy said that, while they did not sound like the Singer Tract kents, they were somewhat similar to the calls we recorded in March 2017 and were unlike any Blue Jay he had ever heard. Jay agreed that they did not sound like a Blue Jay. I thought I noted what I describe as a creaky quality that I associate with Blue Jays, but I heard the calls least well, can’t be sure, and trust Guy’s ear more than my own. Regardless, the descriptions of the calls are what I find most interesting.
On the spot, Jay gave “Yamp-Yamp-Yamp” as a transliteration of the sounds. This transliteration appears in the literature and is rather obscure. While it is mentioned by Steinberg, Jay was unaware of that reference or its source, George Lowery, who used it in his Louisiana Birds, now out-of-print.
More on “Yamp” as a transliteration below. Suffice it to say that the variability among transliterations and descriptions of ivorybill sounds, including but not limited to “kent” and “yamp”, is indicative of a considerably broader range in pitch and duration than the Singer Tract recordings and the strict parameters used by Cornell in Arkansas would suggest.
Guy, too, used a variant of “yamp” to describe the sounds, as shown in these excerpts from his field notes:
The documentation that I wrote down for myself on what we heard on the afternoon of 1/1/19 was “a whining, nasal, rising yaaAMP, yaaAMP, yaaAMP, yaaAMP.” I think in my renditions on-the-spot I was verbalizing “waaANK, waaANK,…”.
“Nasal” was my own word, not having remembered (or known) anyone having used the term in days gone by in reference to ivorybill calls. I am curious as to whether any of our forebears have also described a rising inflection in any ivorybill calls. The kents I heard from the Arkansas bird in October 2005 did not have a rising inflection. They were the sharp single kents and a few double kents (the doubles being HIGH-low) with a tin trumpet quality, distinctly different from what we heard on 1/1/19.
I have never heard before in my life what we heard on that afternoon. There were no archival matches. I think you could probably tell by my expression and reaction that I was stumped in North America for the first time in a very very long time. A couple decades, I’d say.
I’m aware of a reference to Lester Short using “yamp” in discussions about the Cuban ivorybill, but as far as I know, the published references all come from Lowery’s Singer Tract observations. Interestingly, Frank used it too, in our first email exchange.
Here are several descriptions from Lowery:
“The birds were feeding energetically on dead stumps and low trees, and were calling frequently with their peculiar, nasal, rather high-pitched yaamp-yaamp until finally disturbed, after which they retreated to the taller timber and were lost from sight.”
John S. Campbell, J. J. Kuhn, George H. Lowery Sr., George H. Lowery, Jr., “Bird-Lore’s thirty-fourth Christmas census (Tallulah, La.).” Bird-Lore 36 (1934): 55.
Through the woods came the loud clear, high-pitched, “yaamp-yaamp,” unmistakably the call notes of the ivory-billed woodpecker.
Its notes are clear and distinct, and yet rather plaintive. They may be heard at a considerable distance, perhaps a half mile, and have been likened to the false high notes of a clarinet or a ten-penny horn. From my experience I would not say that the notes are repeated any definite number of times in succession. As mentioned before, the notes can be described as a monosyllabic “yaamp-yaamp” with a decided nasal twang.
George Lowery, Jr., “The Ivory-billed Woodpecker in Louisiana.” The Proceedings of the Louisiana Academy of Sciences 2, (1935): 84-86.
. . . our ears strained for only one sound – the high-pitched, nasal yamp, yamp, or as some people interpret it, kent, kent of an ivorybill.
(3) a high-pitched nasal call note that may be described as yamp, yamp, yamp instead of a flicker like, deep voiced, cuck, cuck, cuck.
George Lowery, Jr., Louisiana Birds (1955), 415-419.
I don’t think Frank had read Steinberg when he wrote this in fall 2008, and I’m almost certain he was unfamiliar with Lowery’s book, which was long out of print by then. Frank was a musician and had an excellent ear.
Odd you should mention “yank”…Sounded more like “yamp” to me…very first sighting in 93-94 bird made noise like that twice. When told that to ******** LA Natural Heritage Foundation, he said not IBWO and bye now….Have heard similar sounds in HZ…Have some recorded…Will not make you listen unless you ask;-)…
Frank Wiley, October 2008.
I don’t recall what became of those recordings but it’s intriguing that this little-known transliteration has been used more than once to describe sounds heard in Louisiana.
I’ve heard many stories like Frank’s. He was remained annoyed by his treatment over the “93-’94” bird and talked about it often. The incident illustrates how easy it is for local reports to die in desk drawers and how only a limited number of them reach those who keep track of such things. Several years after Frank sent that email, we met the official; he had no memory of the incident.
It’s always encouraging to have possible auditory contacts, which are infrequent but which often seem to come in clusters. Nevertheless, I’ve become somewhat jaded and tend to minimize their importance. Guy and Jay (for whom it was the first possible encounter) were a lot more excited than I, but for my part, I can safely say that I always enter the habitat with some hope but very low expectations. Every possible encounter is a surprise.
Finally, here are some of Erik’s pictures from the trip, and three of mine, including his first Red-cockaded Woodpecker captures.
Wishing everyone happy holidays and the best for 2019. While the blog has been quiet for a couple of months, the effort continues. A number of items are in the works, and I hope to have news about them in the coming months. And of course, I hope to be able to report on new encounters and new data. My long promised discussion of evidence and the standards applied to the ivorybill is still very much on my mind, but I’m not sure when I’ll be ready to tackle it here; the subject is complicated.
Meanwhile, I thought I’d repost the final section of a trip report posted in late winter 2016, for the benefit of new readers and those who might have missed it then. In retrospect, I buried some very important material at the end of a long post dealing with other matters. I think this content deserves more attention, since it is definitive with regard to conditions in the Singer Tract when Tanner was conducting his study and is more useful in that regard than either Tanner’s statements or Richard Pough’s report, which took issue with some of those statements and perhaps overstated the case in the other direction.
The next morning, I drove to the Wetlands and Aquatic Research Center (formerly the National Wetlands Research Center) in Lafayette and met with Wylie Barrow, Heather Baldwin, Tommy Michot, and Philip and Eric Vanbergen. (Two young enthusiasts who will be helping us out.) Frank joined us briefly, and then Wylie, Tommy, the Vanbergens, and I went out to lunch. It was an exciting and thought-provoking day, and the Research Center is an incredible facility. Wylie and Heather shared their comprehensive and in-depth analysis of conditions in the Singer Tract in Tanner’s day. They’ve amassed an array of materials encompassing land records, Civil War era maps, and stereographic aerial photographs. Their research far surpasses my own speculative effort. It covers the finest details – roads, improved and unimproved, snag densities, tree mortality, conditions around roost and nest sites, as well as conditions in other locations where ivorybills were seen. Tom Foti has done complementary research on hydrology, soils, and vegetation.
Their presentation convinced me that I’ve been too hard on Tanner in some respects. There was a little more old growth in the Singer Tract than I had inferred from the Pough report and some of the historical documents. Nonetheless, the characterization of the Tract as a whole as “virgin” forest is somewhat misleading, since over a quarter of it was second growth, and some of it fairly young. Heather and Wylie have graciously given me permission to summarize some of their findings.
When Tanner began his study, 72% of the Singer Tract was old growth. (Tanner estimated it at over 80%.) Logging in 1938 reduced that percentage to 67%. The ridges, which Tanner deemed to be the best ivorybill habitat, were actually the least likely areas to be old growth. (Tom Foti’s analysis also points to a preference for higher, drier locations.) The regrowth percentages for each landform in Tanner’s day are as follows:
Low ridge (23%)
Total on ridges (32%)
Low flat (4%)
Cypress brake (4.5%)
For the most part, the second growth forests were not particularly old, as has been suggested in previous posts. According to Heather, most of these areas only started to regrow in the 1880s and 1890s, “due to consecutive depressions and low cotton prices”. Thus, parts of the Singer Tract were relatively young second growth, and this included one of the ivorybill home ranges and one that Tanner deemed to be “best” – Mack’s Bayou.
The nature of the habitat in the Mack’s Bayou area is immediately apparent from the 1938 aerial photos, which suggest forest conditions that are present in many parts of Louisiana today. Nevertheless, Ivory-billed Woodpeckers nested there in 1934 and 1935, at minimum, and did so successfully at least once. This fact alone refutes the idea that Ivory-billed Woodpeckers are old growth dependent. Heather informs me that there was an abundance of dead and dying trees on the eastern side of the Mack’s Bayou range, due to a fire caused by logging activities. In any event, the home range Tanner delineated in this primarily second growth area is no larger than the home range he delineated around John’s Bayou, which had more mature forest. In fact, the area he designated as “best” for ivorybills around Mack’s Bayou was slightly smaller than its older equivalent near John’s Bayou.
Tanner knew that a significant portion of the Mack’s Bayou home range was not old growth, since his 1941 map shows “old fields” in the heart of it. He seems to have been unaware of the resurgence of cotton growing during the 1870s and 1880s, so he may have overestimated the age of the forest on that basis. I can’t help but wonder if he glossed over the conditions in the Mack’s Bayou range in part for the sake of protecting the Singer Tract and (as Heather suggested) in part based on what he deemed to be best for the birds from a conservation standpoint, an approach that later ossified into a categorical set of beliefs about old-growth dependence.
As I and others have been arguing for years, extensive forest cover, sufficient dead and dying wood, and enough large trees for roosting and nesting are probably the main requirements, even if old growth or near-old growth conditions are optimal.
I have reviewed the entire late August-late October card and some of the June-August card for what we’ve designated as deployment 5 – a three-years dead Sweetgum stub discussed last summer. Based on approximately six months of data from this deployment, I think squirrels can be excluded as the source of extensive bark removal from mature, thick-barked hardwood boles, just as the data suggest that Pileated Woodpecker can be excluded as the source of scaling on hickories.
The only potential sources of the extensive bark removal under discussion are gray or fox squirrel, Pileated Woodpecker, and Ivory-billed Woodpecker. Pileated Woodpeckers appear to be unable to remove large quantities of bark from hickories in large pieces, and squirrels appear to be unable to do so on the weaker, thinner-barked sweetgums. Based on trail cam captures obtained thus far, Ivory-billed Woodpecker is the likeliest source for the extensive bark-scaling on hickories that we’ve found infrequently in our search area and that I’ve hypothesized is diagnostic for that species.
There were no woodpecker hits on this target tree, but there are multiple sequences involving squirrels. There was minimal little bark removal, and only from previously scaled areas. In fact, I have only detected one visible change to the bark. A small quantity was removed on June 9, between 11:44:13 and 11:44:33. This is shown in the details below.
Squirrels were active on this scaled patch over the course of the deployment, but whatever removed the small strip of bark on the lower right did so during that 20-second interval and was not captured on the trail camera. I think a woodpecker of some sort is probable, since a squirrel would likely have been visible on the trunk in preceding or subsequent frames.
More importantly, squirrels were captured on or around the scaled areas on multiple occasions, and the captures shed light the way they interact with bark on standing boles and what may limit their capacity to remove it.
This deployment ran from August 19-October 21. Squirrels were detected on 17 days and on or near the scaled surfaces on at least 6 of those days. As previously documented, squirrels displayed interest in the edges of the scaling and frequently appeared to be gnawing; however, they removed little or no bark. We now have numerous captures of squirrels on target boles, both scaled and unscaled, and no captures showing them removing bark in quantity or in anything other than small strips.
Squirrels are clearly capable of rapidly and efficiently removing bark from limbs, downed trees, and thinner barked boles. However, I think there are physical limits – body structure and incisor length – on their capacity to remove thick bark from standing boles.
The following images and time lapse clips show what squirrels do when confronted with thicker bark and suggest that when hanging onto a standing trunk, they lack the leverage to remove bark quickly and leave large pieces behind. This should apparent in the selection of stills and video clips shown below as well as in the sequences posted previously. (A brief discussion of squirrels on hickories follows the images.)
Up to now, I have not been differentiating among squirrel hits on targeted trees, squirrel hits on or near scaled surfaces, and squirrel hits in other parts of the frame. Suffice it to say there many, far more than woodpecker hits on both sweet gums and hickories. Squirrels frequently show an interest in the scaled surfaces and also in other damaged areas (like the fracture in the hickory bark shown below). To date we have no examples of squirrels removing any bark from hickories, regardless of condition. It stands to reason that the limits of their capacity on hickories would far exceed what limits their capacity on sweet gums.
I’ve gone through some additional cards and have some more data on squirrels from the deployment that had squirrel captures earlier this spring. As with the results for Pileated Woodpeckers foraging on hickories, I think this tends to exclude squirrels as the source of extensive scaling on standing mature boles. That will be the subject of the next post, which should be up within a week. In the interim, here’s the October trip report I’ve been promising.
We had no possible encounters and found little suggestive feeding sign this time around.
I spent the first two days with Matt Courtman (and his brother on the second day) in the vicinity of last November’s Saucier sighting. The first day was rainy enough to depress avian activity but not quite enough to keep us indoors. The ground was wet but mostly not unbearably muddy.
The second day, we found a scaled sugarberry (Celtis laevigata). Tanner called this species hackberry, which is the common name, but it’s not to be confused with the common hackberry (Celtis occidentalis), which is found farther north. Despite the appearance, the tree was either barely alive or very recently dead, since leaves were still visible on the upper branches.
Sugarberry bark is thin, and it can fracture and break off in large chunks. Pileated Woodpecker is a possibility for this type of scaling, but it is interesting nonetheless, and it strongly resembles ivorybill work on a sugarberry (mislabeled as a “gum”) photographed by Allen and Kellogg in the Singer Tract.
There were also horizontal bill marks on the surface of the wood. These were interesting and perhaps suggestive; these superficial scratches are the only horizontal markings on sapwood that I think may be suggestive of ivorybill.
There is so much potential habitat in this area that I’m unsure how to go about searching it, given our small team and limited time and resources.
I spent the balance of my time in our main search area. Tommy Michot and our new team member (I hope to include some of his photographs in a future post) joined me for part of the trip. Because we now have 8 functioning trail cams in the field, much of my time is devoted to servicing the cameras and changing cards.
On the last day, Matt, Lauren (his wife), and I explored a very narrow corridor of near old-growth forest that stretches for several miles to the east of the main search area. We also spoke to someone who had ivorybill sightings, though not recent ones, in the area discussed in this post.
We found more fresh beaver sign than I’m used to. The tree shown is an ash, uncommon in our search area.
It was a very snaky trip. I had a few near misses with cottonmouths. A coral snake was a major highlight, spotted and avoided on the road by the new Coyote. I was even able to capture it briefly on video before it buried itself.
We saw turtles too.
And all the rain meant fungi were plentiful (including a meal’s worth of chanterelles, not shown but brought home and enjoyed).
There was plenty of woodpecker activity, though it was sporadic, and there was not much drumming. It’s always tough to get good pictures with leaves on the trees, but this Red-headed Woodpecker was cooperative.
In all my years of searching, I had never found the remains of a Pileated Woodpecker until the trip before this one. It’s a little unnerving for this to happen back to back. I also found Red-shouldered Hawk remains (though not in the same vicinity). I worry that these birds may have been shot, though there’s no evidence for it. The remains, feathers and a few bones, were on top of a log, suggesting that a raccoon was the last creature involved.
One of our trail cams was hit by a falling limb, and was aiming skyward when found. It appears to be functioning and has been re-aimed at the target tree (where there was an intriguing capture in the summer of 2017).
We didn’t find much interesting scaling, although some of the work we found was on oaks, which is rare.
I don’t know the tree species, and Pileated Woodpecker is a possible source, but the work below is unusual. Edith Kuhn Whitehead once told Frank that cambium shredding, possibly like that shown, is suggestive of ivorybill; however, I only heard this second-hand and am not clear about what she meant.
The sunrise on my last field day was spectacular.
Stay tuned for squirrels . . .
I’ve completed reviewing the cards from the deployment discussed in three previous posts. As it turned out, the most dramatic and informative sequence was captured on July 29; it was the last sequence found in the course of the review.
To recapitulate: the tree is a hickory, and hickory bark is uniquely tough, tight, and hard to remove; when first found in early 2017, the tree had already been extensively scaled, probably during the spring and summer of 2016; additional and extensive scaling took place between early 2017 and early 2018; at the time the trail cam was first deployed in April 2018, I’d estimate that over 30% of the entire surface area of the tree had been stripped of bark.
This type of very extensive scaling on hickories has a distinctive appearance, and I hypothesize that it is diagnostic for Ivory-billed Woodpecker. I further hypothesize that it is beyond the physical capacity of Pileated Woodpeckers to do this type of work. We have not yet documented whatever is doing the initial scaling (which is the main objective of these deployments), but data collected thus far on Pileated Woodpecker foraging on hickories tend to exclude this species as the source of the initial work.
Minimal additional bark removal took place between April and October 2018, and all Pileated Woodpecker visits to the targeted part of the tree were captured by the trail cam, except for any that may have occurred between August 12 and August 21, when the camera malfunctioned. The images below are from the beginning and end of the deployment, and they reveal just how little bark was removed over a nearly six month period, when Pileated Woodpeckers visited the tree at least 23 times.
The breakdown of those visits may be related to beetle abundance near the interface of bark and sapwood; this could be relevant to peak ivorybill foraging times as well, although there were no possible ivorybill captures during this deployment.
Pileated Woodpeckers (alone and in pairs) visited the tree 10 times between late April and June – on May 1, May 3, May 8, May 12, May 21, May 25, May 28, May 30, June 1, and June 4. There were nine visits between June 17 and July 3, (with two sets of of captures on June 17 and July 3rd). Hits dropped off dramatically after July 3rd. There were none between July 4 and July 25 and one each on July 26 and 28. The final hits were on September 24 and a very brief one on October 5.
The duration of these visits ranged from approximately one minute to over 20 minutes. At just under 15 minutes, with two birds present, the July 29th clip is one of the longer ones. Immediately below are the captures from July 26 and July 29 and a version of the July 29 capture at 1/10 speed, which makes it easier to see what the birds are doing while on the trunk. The relevant part of the clip ends at just after the one minute mark. If you have the capacity to download the captures and step through them frame by frame, that will also be helpful. Some additional discussion after the videos.
This capture shows the most extensive single incident of bark removal by a Pileated Woodpecker over the course of the deployment. It’s also the only incident in which bark is removed from an area that is not an edge. The area in question is on the upper right.
I think this illustrates the Pileated Woodpecker’s very limited capacity for bark removal on hickories. It takes the bird several minutes to remove approximately 8″x2″ of bark (crudely estimated, based on the size of the woodpecker). This is roughly equal to, and possibly less than, the area of many of the individual chips found under the homepage tree. In addition, it appears that the PIWO removed the bark by excavating through it, not by stripping it.
It’s also worth pointing out that the snag and remaining bark are farther along in the decay process, and hence the bark is likely easier to remove, than when the first two rounds of scaling took place.
This is congruent with what I’ve hypothesized; Pileated Woodpeckers are very well adapted for excavating, and they are capable of digging through even tough, dense hickory bark; however, they appear to be excavating but not to be capable of removing it by scaling in large chunks.
We will continue to collect data, which may end up contradicting the findings thus far, all of which suggest that some other animal is responsible for the initial, very extensive scaling. The main purpose of this deployment was to document what woodpecker activity on a tree that had already been scaled; I expected that this would involve Pileated Woodpeckers, not ivorybills. It will take considerable luck to predict which trees are likely to be scaled and capture whatever is doing the initial bark removal; that’s the primary focus of this effort. There are a lot of hickories in the woods, and we’ve only found a handful of impressively scaled ones over the years.
The original post from last week is below the updated material. It provides some important background, and I encourage you to read all the way and watch the clips.
A couple of prefatory notes for new readers: first, this discussion pertains to hickories only because the bark of trees in the genus Carya has characteristics that make it much harder to remove than any other type of tree in the southeastern U.S. Second, the video clips are time-lapse composites of images shot at 20 second intervals.
I’ve gone through most of the June-August captures from the deployment discussed in the original post and have found a number of additional examples showing one or two Pileated Woodpeckers foraging on the scaled areas. I’m including those captures and a couple of individual frames that should help illustrate what’s being described.
Pileated visits to the target tree spiked starting on June 17, with two visits on that day, one on June 18, and one on the 20th, 23rd, 24th, 25th, one on July 2, and two on July 3. There were no hits between July 4 and July 10 and no hits between August 2 and August 12. Imagery for July 11-August 1 has yet to be reviewed.
Of the sequences below, the ones from June 17, 18, and 25 are probably the most informative. They suggest that when Pileateds remove hickory bark, even on a tree that is considerably more decayed than some on which we’ve found scaling, they do so by focusing on the scaled edges, and when they do remove bark, they’re more likely to dig through it (as I’ve hypothesized) than to pry it off in flakes.
We have now obtained 22 sequences of Pileated Woodpeckers investigating or foraging on and around extensively scaled hickory boles, the first one dating back to 2013. Some captures involve lone birds and others involve pairs. Duration of the visits ranges from under 1 minute to upwards of 20 minutes. In these captures, Pileated Woodpeckers remove bark in modest quantities and with difficulty, when they remove it at all. They never scale extensively or remove bark in pieces approaching the size of those found under the homepage tree, and there is nothing in the footage obtained that suggests they are capable of doing so. I think this tends to exclude Pileated Woodpecker as the source of the initial work on hickories.
These stills should shed additional light on Pileated Woodpeckers and bark removal.
The additional sequences are below, followed by the text of the original post.
I just returned from Louisiana where I visited both the search area and the location of Joseph Saucier’s sighting last year. There were no possible encounters on this trip and just a little of potential significance ivorybill-wise. I plan to post a trip report within in the next week or so and hope to get to the long-promised evidence post in November. There may be additional posts about trail cam results if anything significant shows up. There are numerous cards to review, and I have a lot going on in a variety of arenas, but I’ll do my best to keep you all updated on a regular basis.
I’ve gone through the card for one of our deployments between August 21-October 20. The June to August card has yet to be reviewed, but these results are informative in their own right, especially in conjunction with the results from April and May, discussed here. I think they tend to support the hypothesis that Pileated Woodpeckers are not responsible for the bulk of the bark removal on live or recently dead hickories and at least indirectly to support the hypothesis that Ivory-billed Woodpeckers are the only creature capable of doing this type of work. (Go here for a discussion of squirrels as a potential source.)
At Tommy Michot’s suggestion, we’re also going to start quantifying our results, including all hits that we note, regardless of what kind of animal is involved. Those results appear at the end of the post.
Like two other current target trees, which are sweet gums not hickories, I selected this one because it had already been scaled (extensively in this case); the remaining (majority of) targets have been chosen in hopes that they will be scaled in the future. For most of the hickories we’ve found, including ones that I’ve watched for extended periods of time, the bulk of the scaling appears to have been done in a single visit.
We’ve found only one example of a tree with truly fresh scaling, the home page tree. That work, found in May 2013, was probably no more than a week old, since the trunk was wet with sap and the tree died soon after. Numerous large chips were found at the base. All other examples appear to have been less recent, and in most instances, flooding appeared to have washed bark chips away.
After reviewing the captures, I was inspired to revisit the history of this particular snag, which Phil Vanbergen found in early March, 2017. It had been extensively scaled at that time, I suspect during the spring or summer of 2016 but possibly the year before. Phil found a few small chips at the base, but given the extent of the scaling, it is safe to assume that the overwhelming majority of the chips associated with the initial work had been washed away in one of the flooding events that had taken place during the intervening months. Phil shot this video of the tree, which shows the work extending from mid-bole up to the point where the crown had broken off; I later found what I believe to have been the crown, and it too had been scaled.
What sets this tree apart, is that there appears to have been a second extensive scaling event between March 2017 and March 2018 when I re-found it. While there had been a couple of floods in the course of the year, one large and a couple of medium-sized chips remained near the base of the snag, but it was apparent that most had been washed away.
We deployed a trail cam on the tree in April, and one of the early frames from that deployment more clearly shows the extent of the second round of scaling, which reaches to near the base of the snag.
A comparison of that frame, one from the beginning of the mostly unreviewed June-August card, and a capture from October 21 of this year shows how little bark has been removed by Pileated and other woodpeckers over the course of just under six months, with modest quantities removed from the bole, as indicated by the arrows.
Pileated Woodpeckers appeared in two captures between late August and late October, a far lower rate than in April and May. The first capture, from September 24, involved one bird, which spent several minutes on the target tree and did little additional damage. The other, from October 5 involved two birds and was fleeting but cool to see. The time lapse clip and the three captures are below
Pileated Woodpeckers are abundant in the area, but we have yet to obtain any evidence that they can remove large chunks of bark from the boles of live or recently dead hickories and scale them rapidly and extensively; indeed, all the evidence obtained thus far is that they remove bark in small pieces, slowly and inefficiently.
Past observations suggest that the peak period for scaling of these hickories is between May and October. This appears to be the time frame when Hesperandra polita, the heartwood dwelling Cermabycid identified as infesting one of our scaled hickories, are likeliest to be found under the bark, as larvae and adults, or close to the bark layer in pupation chambers. The adults shown below were collected from under bark on June 28, 2013.
In the case of this snag, at least, Pileated Woodpeckers removed little bark during the probable peak scaling period. The other side of the tree remains unscaled. In addition, we’ve found this work infrequently over the years, and the scaling on the lower part of this tree is the only new example of this kind of foraging sign found in the past year. All of this points to something other than Pileated Woodpecker, and I would suggest something rare, as the source of the scaling.
Regarding the hits over the course of the deployment, I’m counting a “hit” as the appearance of an animal in a frame or series of frames, including interrupted series in which the animal reappears after a break of a minute or two. Impressionistically, this deployment is considerably more active than some. Even so, there were no hits on 17 of 62 days.
The most frequent hits were lizards (mostly on the target tree): 46 hits.
Passerines, including Hooded Warblers, Carolina Wrens, and Cardinals, were next with 24 hits, followed closely by squirrels with 22.
Woodpeckers followed – 2 Pileated hits, one involving two birds, one Downy and one probable Yellow-bellied Sapsucker toward the end of the deployment.
There were two hits each for beaver, deer, and moth or butterfly (one likely a luna moth).
Finally, there was one apparent Barred Owl and only one hog, which was surprising given their abundance in the area.
Stay tuned for the trip report . . .