Brief Update and A March 2017 Compilation

Compilation of Calls and Knocks from Matt’s March 2017 Recording

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.


Season’s Greetings and Singer Tract Conditions Revisited

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:

Ridge (43%)

Low ridge (23%)

Total on ridges (32%)

Flat (9%)

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.

 


More Squirrels and No Scaling on a Mature Sweetgum

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.)

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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.

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Trip Report: October 17-22, 2018

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.

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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.

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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.

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Bark scaling on sugarberry. Hand-colored photo by Arthur A. Allen.Courtesy of the Division of Rare and Manuscript Collections, Cornell University Library

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.

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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.

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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.

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We saw turtles too.

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And all the rain meant fungi were plentiful (including a meal’s worth of chanterelles, not shown but brought home and enjoyed).

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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.

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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.

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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).

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We didn’t find much interesting scaling, although some of the work we found was on oaks, which is rare.

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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.

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The sunrise on my last field day was spectacular.

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Stay tuned for squirrels . . .

 


Final Installment: Trail Cam Deployment and Pileated Woodpecker Hits April-October 2018.

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.


Updated with More Pileated Woodpecker Clips: Trail Cam Results and More on a Camera Trap Tree

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.

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Suspected IBWO hickory chips

 

 

 

 

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.

 

 

 

 

 

 

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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.

 

 

 

 

 

 

 

Bark Strips

Small Strips Found by Phil Vanbergen at Base of Scaled Hickory, Presumed Source is Pileated Woodpecker

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Downed Hickory Top showing suspected ivorybill scaling.

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 . . .

 


Trail Cam Results and More on a Camera Trap Tree

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.

 

 

 

 

 

 

Bark Strips

Small Strips Found by Phil Vanbergen at Base of Scaled Hickory, Presumed Source is Pileated Woodpecker

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Downed Hickory Top showing suspected ivorybill scaling.

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 . . .

 


Historic Range Hypothesis: A Bits ‘n’ Pieces Epilogue

In retrospect, I realize that I could have stated my hypothesis about historic range more explicitly in the Bits ‘n’ Pieces series, here, here, here, here, here, and here. My treatment of this subject draws on and expands upon Tanner, Jerome Jackson’s extensive review of the historical record, the work of Benjamin Leese, and Appendix E in the U.S. Fish and Wildlife Service’s Ivory-billed Woodpecker Recovery Plan, supplemented by my own research and review of the source material.

I got somewhat too focused on specimen records and even more so on habitat types. The version of the map I created for the series reflects that focus, by including barrier islands, for example. The subjects of range and habitat are of course intertwined, but I’ll state the hypothesis with respect to range upfront and follow it with a more detailed discussion:

The Ivory-billed Woodpecker’s range was considerably more extensive and than is recognized by the general public and than has been represented in much of the literature, both popular and scientific. All published range maps of which I’m aware, including Hasbrouck’s (1891), Tanner’s (1942), Jackson’s revised and redrawn version of Tanner (2004), and online, poorly reflect the historic range, especially east of the Mississippi.

This has implications in terms of habitat requirements and adaptability as well.

I suggest that the northern limit of the ivorybill’s range was just above 40 degrees North and that the western limit was approximately 98 degrees West. There are no archaeological or other records from over 2000′, so I’d exclude higher elevations in the Appalachians and Ozarks. I think the previous maps are accurate to the extent that they show the range as extending farther west in the Red and Arkansas River basins than in the Missouri.

To express it somewhat differently, I think ivorybills could be found as far north as the lower Delaware River on the Eastern Seaboard and that they could be found in riparian corridors into the lower reaches of the Appalachians from there south.

In Florida, I think it’s conceivable that the range extended to the Upper Keys. In the southwest, I’d draw the line near Port Lavaca, Texas to west of Tulsa, Oklahoma. Except for an archaeological find in northeastern Nebraska that almost certainly involved trade items, the northernmost specimen record from west of the Mississippi is from Forest Park, MO (more on that below).

The story seems to have been somewhat different in the Ohio River watershed, where both archaeological evidence and sight records suggest that birds were present far upstream from the Mississippi confluence and along tributaries well north of the river itself.

I’ve created another map showing both the limits of my hypothesized range and selected reports from what could be considered the edges of that range. A screen cap is below. Click on this link for annotations. Although some of the records are pre-Columbian (the earliest estimated as dating to 0-200 CE/AD), I suspect this was the approximate range until the mid to late-18th century.

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Hypothesized limits of Ivory-billed Woodpecker range and selected records from areas outside those shown on most other maps.

Thus my hypothesized range is considerably more extensive than the conventional one (shown immediately below). On the Eastern Seaboard, it extends much farther north and also farther inland. It is far greater within the Mississippi watershed, extending to north of Columbus, Ohio, and encompassing all but the higher elevations in the Appalachians (based on the archaeological site at 2000′ near Lebanon, VA), reaching farther north and west in Arkansas and Missouri.

It was also somewhat more extensive in Texas and Oklahoma, reaching farther into the plains and a little farther south than the maps suggest. Outside of coastal areas, the presence was probably limited to riparian corridors, with those in the western part of the range (at least) being narrow. The version below is from the IUCN Red List entry for the ivorybill.

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IUCN Map derived from Jackson’s revision of Tanner’s 1942 publication. Similar maps are widely reproduced.

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Hasbrouck’s Ivory-billed Woodpecker Range Map (1890). Shaded areas reflect what Hasbrouck believed to be the range at the time of writing.

While what I’m suggesting may seem heretical to some, it’s well-supported by the archaeological record, accounts from early explorers and naturalists, and collection records or reports thereof, albeit to a lesser extent. I covered many of the records that led to my formulating this hypothesis in previous posts; I won’t recapitulate all of them here, but one passage is worth revisiting. Two notes on technical terminology: middens are most easily defined as “dumps for old domestic waste“, and tarsometatarsi are the lower leg bones found in birds (and some dinosuar fossils).

If our knowledge of the Ivory-billed Woodpecker were based on the archaeological record alone, we’d think of it as an upland species. Further, we might very well assume that it ranged from the hills of Georgia, to the Alleghenies in Virginia, to central Ohio and west-central Illinois. 

The remains found in Native American middens were unlikely to have been trade goods; ivorybill parts seem to have been a valuable commodity for ceremonial use west of the Mississippi but not east of it, and in several cases, the remains found were tarsometatarsi, which would be consistent with use as food:

There is strong physical evidence of  ritual value for woodpecker scalps and bills from the upper Midwest and Plains . . .  Remains of the Ivory-billed Woodpecker can be found in sacred bundles, on pipe stems, on amulets, and with burials among the Native Americans of the region. The evidence comes from the western Great Lakes and the Plains; no evidence of a particular use of Ivory-billed Woodpeckers has yet been uncovered from the eastern area of the Great Lakes (Ohio, Indiana, and Michigan).

(Leese, 2006.) Leese also points out (in several of his publications) that there’s no evidence that ivorybill parts other than scalps and bills had any trade value.

In an unpublished 1989 update to his monograph (housed in the archives at Cornell), Tanner accepted additional reports, including archaeological finds from Scioto County, Ohio (15th or 16th-century) and Madison County, Illinois (Cahokia Mounds, approximately 15th-century), as well as a collection record from Forest Park, Missouri and an 18th century record from Lincoln County, Kentucky. Since that time, additional archaeological records from Georgia, Virginia, West Virginia, and Ohio have turned up.

Thus, the case for ivorybill presence both in the lower reaches of the Appalachians and well up the Ohio River (and its tributaries) is compelling, and any suggestion that items found in Native American middens might be trade goods is pure speculation with no evidence to support it.

In a paper titled, “Putative Records of the Ivory Billed Woodpecker in Pennsylvania and the Mid-Atlantic” (2016 Pennsylvania Birds, 20(2):71-72), Leese suggested that eastern Pennsylvania and Southern New Jersey might be the northern limit on the Atlantic Coast. I agree and might even go a step further and argue that the available evidence strongly supports that view. The discussion below relies heavily on material Leese discovered, though I disagree with Leese’s conclusion that a more extensive range and more varied habitats support Snyder’s argument that hunting was the “main cause of the species’ extinction”.

This idea that ivorybills ranged so far north on the East Coast will probably be the hardest for many to swallow. Bear in mind, however, that Audubon described the ivorybill as an accidental in Maryland. Audubon’s discussion of range is odd; he didn’t mention Florida, and there’s nothing to support the idea that the western part of the range extended to the foothills of the Rockies. But he would have been far better informed about the Eastern Seaboard.

In any event, his description dates to the 1820s, by which time the range was likely shrinking. As discussed previously in the series, I suspect that the extirpation of the beaver played a major role in the ivorybill’s decline outside of Florida. Beavers were probably extirpated in New Jersey by 1820 (Van Gelder 1984). It’s reasonable to infer a similar date for eastern Pennsylvania.

To expand on this beyond the previous posts in the series, Peter Kalm, a prominent European naturalist and student of Linnaeus, listed the ivorybill as present in the Delaware Valley and distinguished it from the Pileated, which he described as “a Black Woodpecker with a red head” and “frequent in the Pennsylvanian forests”.

It’s not clear whether Tanner was aware of Kalm’s 1749 record, which was described in The Auk in 1903. The author of that paper suggested that this record should be taken “cum grano salis,” primarily because there have been no other records from the state. Or have there?

While it is ambiguous, Leese discovered a letter from Alexander Wilson, written during the early years of his career, when he was living on William Bartram’s property near Philadelphia; it is strongly suggestive of ivorybill, describing a large and “most extraordinary Blackheaded Woodpecker”. This was at a time when Wilson seemed to be in the process of learning his birds, and he did not mention it in later correspondence, which leaves room for doubt.

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While Wilson’s description is not very detailed, I find it suggestive. And as noted previously, I think the only basis for rejecting Kalm’s account (and he seems to have otherwise been meticulous) is what we think we know about the ivorybill, a knowledge base derived from observations dating to between 60 and 190 years later. While there’s no way to prove it, I think Kalm’s listing should be treated as credible; it would be if a more common species were involved. Leese mentioned a couple of additional 18th century reports from Pennsylvania (included on the map) but found them questionable.

I’m not aware of anyone else having made this observation, but I think it’s a very important one. In the 1740s, the ivorybill had not yet acquired the mystique that would accompany it from the mid-1800s to the present, a mystique that was popularized if not invented by Audubon. This lends greater credibility to earlier reports such as Kalm’s. I think the same principle supports Jefferson’s listing of the ivorybill as resident in Virginia (which may have been based on his own observations) a couple of decades after Kalm and a few decades before Audubon.

To return briefly to Wilson and another report from an unexpected location, Jackson (2004) references a specimen collected by Wilson from somewhere between Winchester, Virginia and Martinsburg in what is now West Virginia (presumably in the Potomac watershed). I have not located the primary source for this reference, which may be in the archives of the Philadelphia Academy of Natural Sciences, but here’s Jackson’s:

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The Putnam County, WV find is also interesting, as it suggests a bird that may have been collected for trade rather than being acquired through it.

I want to touch briefly on two additional records, both involving specimens. The facts related to these records point to how even specimen evidence is not free from ambiguity. For one thing, specimen tags often reflect shipment rather than collection locations. In addition, labels could have been changed and replaced at any point in the chain of custody between hunter and museum.

The first specimen is housed at Cornell (and I have seen it myself). It was collected in 1898 from the “Florida keys”. In Appendix E of the Ivory-billed Woodpecker Recovery Plan, it is suggested that this might actually refer to one of the forested “keys” in the Everglades rather than to one of the offshore islands. However, given the ivorybill’s use of barrier islands on the Atlantic Coast and the 10,000 Islands in Florida, it does not seem farfetched that the specimen could have been collected somewhere in the Upper Keys proper.

From my current perspective, based on the Recovery Plan’s information about habitat on the southwest Florida coast, both possibilities seem plausible and neither is particularly surprising. However, neither location would ever have had many characteristics in common with stereotypical ivorybill habitat –  vast, contiguous bottomland hardwood forests. (Although he sometimes seemed to embrace this stereotype later in life, Tanner recognized that ivorybills lived in varied habitats, as have others who have studied the subject in depth.)

The other specimen, labeled  as being from Forest Park, Saint Louis, Missouri, escaped Tanner’s notice initially but was included in his 1989 update. It is housed at the Colorado Museum of Natural History in Denver and was collected in 1886. Matt Courtman pointed out that by 1886, Forest Park was hardly an isolated spot; it attracted “hundreds of thousands” of visitors a year,was located on the outskirts of a city with a population of 400,000, had been at least partially landscaped, and was accessible by streetcar.

So not only did this collection come from well north of what’s commonly accepted as the historic range; it may have come from a managed parkland on the outskirts of a major city, hardly stereotypical ivorybill habitat. The location and date are surprising, so it’s possible that the specimen was collected somewhere else (though not in a different region) and that Forest Park was the shipping location.

This may be so, but an 1886 collection from anywhere near Saint Louis is a paradigm-buster, regardless of the exact location, as this 1884 map suggests. Forest Park, to the southeast of Florisant and Ferguson, which are indicated by the red circle on the map, is not shown.

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Detail from 1884 map of Missouri, showing Saint Louis and environs. Note both the network of railroad lines and the apparent population density.

Tanner’s original map showed the ivorybill as never having ranged farther north than the Missouri bootheel (the southeastern corner of the state) and as having been extirpated from all but the southernmost tip of that region by 1880. The last specimen collected in Missouri dates to 1895, from just north of the bootheel “eight miles southwest of Morley.” (Widdman, 1908). Tanner seems to have been unaware of this record, which is mentioned in Jackson, who could not locate the specimen itself.

Tanner received at least one report (1937) from Dallas County, Missouri, which is northwest of Springfield, in the upper (southern) reaches of the Missouri River basin and well outside the generally accepted historic range. The source was a local Audubon Society officer, and the letter is archived at Cornell. There appears to have been no follow-up. According to the Recovery Plan, reports from this general area continued until 1949.

Though his map of the range ca. 1890 suggests a northernmost limit in Mississippi and Louisiana, Hasbrouck (citing Cooke, Bird Migration in the Mississippi Valley) mentioned 1884 records from near Kansas City and undated claims of former breeding near Fayette, along the river in central Missouri; Tanner considered these questionable or accidental. I agree that they’re somewhat questionable but not that they could have been accidental, since both purportedly involved breeding.

Reading Cooke reveals that both were second-hand accounts. The Kansas City report includes no details except that birds were observed “during the past few winters”, and “it probably still breeds in that vicinity”. For Fayette, the source was identified as a local farmer and egg collector by the name of Lientz, but the former breeding claim is devoid of any details, including the informant’s name.

Thus, the possibility of mistake or miscommunication exists in both instances, as in the seemingly credible report from eastern Nebraska discussed in Part 2; however, Jackson also references Harris’s Birds of the Kansas City Region (1919), which lists a “Judge Guinot” and others” for the Kansas City area records, in the “deep woods of the Missouri bottoms”. No date is given, but it seems possible if not likely that Guinot (1855-1935) was Cooke’s source

While I think the historic range probably extended as far as Kansas City, the case seems a little weaker to me than it does for the eastern seaboard and Ohio Valley –  given the paucity or absence of archaeological evidence or early reports from the Missouri River watershed, a key route for explorers, traders, and early settlers. For example, Featherstonhaugh, who crossed the Missouri River basin near the confluence with the Mississippi in the 1830s, described the northern limit as being considerably farther south, in the Arkansas-White River watershed. But perhaps there’s more to uncover about the ivorybill’s history along the Missouri.

As with anything ivorybill related, it’s probably best to be comfortable with not knowing and even to revel in the uncertainty.


Trail Cam Captures Redux: Beyond (My) Reasonable Doubt, Part 2

The previous post generated a number of responses, mostly positive, but there were a couple of negative remarks, one of which I thought I should address.

One claim was that this new way of examining the imagery (which was misleadingly described as “enhancement”) confuses the issue and makes the images harder to assess. In reality, the processes used in the previous post and in this one are for the most part not “enhancements.” While I have used various image enhancement tools in the past, most of these treatments use unaltered original images to create composites that make it possible to separate figure from ground and parts of the target from artifacts. It’s not a perfect method, but it’s an illuminating one, even with low resolution images. It requires no special forensic expertise. As should become clear from this post, it can also be useful for estimating size.

The images examined in this post were all captured December 7, 2014 on a Reconyx Trail cam that was showing its age. They were previously discussed here, here, and here.  As in the previous post, I’ve used Luminar to create the composites and apply various effects for this deeper dive. As always, views can be had by clicking on the images themselves; mousing over the images will reveal captions in most instances, and I have added versions with arrows to help orient you. I strongly encourage you to examine the images closely.

One initial comment about these images and the ones discussed in the last post: I’m personally convinced beyond a reasonable doubt that two of those images show Ivory-billed Woodpeckers. The images discussed in this post show fewer details, so they may not be quite as compelling. Either way, the captures under discussion are only part of the mosaic, and the subjective conviction that we have found Ivory-billed Woodpeckers in two locations is not solely dependent on them. The audio from last year, for example, is strong evidence in its own right. Go here for a detailed discussion of evidence gathered since 2009

I’ve reposted the original captures in tiled mosaic form below; I’ll follow that with some composites and comparisons among the images. I think the results are helpful if not quite as revelatory as the ones in the last round.  A very prominent American birder tweeted that one of the images below shows a Blue Jay (9.8-11.8″) and characterized the suggestion that it might be an ivorybill as “crazy”. (This is the capture I think is likeliest for ivorybill in this group.) I think his knee-jerk suggestion is absurd, as this approach to reviewing the images should make more apparent.

 

I’ll begin with the raw image I’ve always liked most for ivorybill, as previously discussed in detail and in comparison with Imperial Woodpecker captures. (Note that the version comparing putative IBWO and IMWO has been enhanced.)

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Suspected Ivory-billed Woodpecker

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Rotated, resized image of Imperial Woodpecker in flight. The bird is angled downward and slightly away from the camera obscuring the bill and foreshortening the profile. An automated motion blur reduction feature has been applied to the image of the putative ivorybill.

The next image shows the difference between the foregoing frame and one captured approximately 40 minutes later. The bird to the left of the snag is clearly closer to the camera (which was approximately 85′ from the target snag), between it and the snag. The composite strengthens the impression that the suspected ivorybill is behind the tree and the foliage behind it, since at least some leaves appear to be between bird and camera. Frank estimated the foliage as being 15′ more distant.

 

In the earlier discussion, several Pileated Woodpecker captures, including the one below, were used for comparison. These captures were taken from a slightly different position, but that’s irrelevant to the issue of size relative to the reference object, the jug handle-shaped stub.

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Pileated Woodpecker on Snag

It may be even more instructive to contrast the capture with the Red-headed Woodpecker, apparently caught as it was preparing to land on the snag. The comparison suggests that the two birds are approximately the same distance from the camera. The possible ivorybill’s body is considerably longer than the Red-headed Woodpecker’s wingspan (14-17″). Thus, between the Pileated Woodpecker (~16-19″, with southern birds typically on the smaller side) and the Red-headed Woodpecker, it can be inferred that the suspected ivorybill is approximately the right size (19-21″), considerably larger than a Red-headed and somewhat larger than a Pileated. I am unable to think of an alternative ID for a bird of similar size and shape, even leaving aside the fact that a white trailing edge seems to be present even in the original, unmodified version of the capture. (The trailing edge becomes more apparent when the image is processed to reduce motion blur.)

 

A different but related method of image processing is helpful for understanding the position of the bird relative to the snag and also suggests that another capture in the series is at least size-appropriate for ivorybill; the tuck and the long, pointed shape of the wings are also intriguing. The first composite shows the unknown bird and the Red-headed Woodpecker. (Note what seems to be a wing, species unknowable, protruding from behind the snag; it appears in the Red-headed frame and no others and had gone unnoticed until now. On looking again, this could also be a squirrel’s tail, albeit unusually positioned.) The second is an overlay of the suspected ivorybill capture and the unknown bird processed using Luminar’s “Color Burn” feature; the two birds appear to be approximately the same size and in the same plane. I’ve added a shot of a Pileated Woodpecker in flight, with wings in a similar position, for comparison.

 

 

 

 

 

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Another capture from the morning of December 7 has always interested us. The underwing pattern and shape are suggestive of ivorybill and reminiscent of one of the Singer Tract photographs. But questions about size have lingered. Comparing this image with two others from the same deployment that show Red-headed Woodpeckers may be helpful, and it has pushed me toward favoring Ivory-billed Woodpecker for this capture as well.

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Either Ivory-billed or Red-headed Woodpecker Depending on Size

 

 

 

 

This capture seems more ambiguous to me, but a few factors are more consistent with Ivory-billed Woodpecker than Red-headed Woodpecker. Both Red-headed Woodpeckers, one captured on the same morning under similar lighting conditions, appear to be closer to the camera than the possible ivorybill. My efforts at measuring wingspan were crude, but the suspected ivorybill seems to have a slightly greater wingspan, despite the upturned angle of the wings and apparent greater distance from the camera. This would tend to exclude Red-headed.

The comparison is also useful insofar as it shows that the wing and body shape of the possible ivorybill are not similar to the Red-headed Woodpeckers captured during this deployment. While Red-headed wing and body shapes can resemble ivorybill at certain angles and under certain lighting conditions, as Bill Pulliam documented years ago, the tail in this image looks too long relative to the body, and the wings look very narrow, at an angle that I don’t think would create an illusion of elongation.

As always, I’m open to correction, and my interpretations are provisional. Intelligent and informed comments are welcome.


Trail Cam Captures Redux: Beyond (My) Reasonable Doubt

I’m making another departure from my posting schedule for reasons that I hope will be self-evident. This is the strongest statement of my views I’ve made to date; I’m calling it as I see it based on this new way of looking at the photographs.  As always, click on the images for better viewing.

A Louisiana photographer (and new Project Coyote member) who has been following our efforts, reached out to me in response to the recent trail cam capture and alerted me to a feature in Photoshop. This feature makes it possible to stack two images and subtract the identical pixels, leaving the differences between the two images visible in the new composite.

I understand that this is sometimes referred to as subtracting and sometimes as ghosting. Given my limited knowledge and skill set when it comes to image processing, this was a revelation. The method is described between minutes 1 and 2 of this YouTube video. (The rest of the segment pertains to image stacking for landscape photography and is not relevant to this discussion.)

He sent me three examples – the recent capture, the neckbird, and a pair of photographs showing what Frank Wiley had identified as a female Ivory-billed Woodpecker in flight. I didn’t get any new insights from the last of these; the results for the most recent capture were interesting and possibly significant; the neckbird was a revelation, eliminating any lingering misgivings I had about the image and convincing me (at least) beyond a reasonable doubt that it shows an Ivory-billed Woodpecker.

Bear in mind that the images discussed below are among a handful of captures (out of well over a million images obtained since 2009) that we’ve found to be suggestive or better. (At the 20 second interval used on our current cameras, a single month’s 12 hour-a-day deployment will produce over 60,000 images; the Reconyx cams had a 30 second interval, but that’s still over 40,000 per camera per month.)  So it’s not as if we’re finding possible ivorybills everywhere, let alone frequently.

I recently started using a different, ostensibly more user-friendly, image-processing program, Luminar, and I found that it has the same capacity. I tried it on the other oft-discussed trail cam capture with the same revelatory result, although in that case, I did not have access to both unprocessed originals and had to use one cropped image and another that had been cropped and lightly processed for brightness and contrast. I don’t think this impacted the results. I used Luminar to process all the images discussed below.

Immediately below is the original “Neckbird” capture and an enhanced crop, followed by the processed image, showing the difference between this frame and the one before it. Next is a detail, showing the ‘ghost’ outlines of the image that appeared in the original. (Note that a second bird may be present in the form of a bill protruding from the lower cavity in the snag at right, as discussed in this post.)

 

 

 

 

 

 

 

For me, the most startling result is that the bird looks even more serpentine and elongated in this iteration. This is mostly because the lower third of the body (apparently including part of the tail) is better resolved and distinguishable from surrounding objects. What I had thought was a patch of white near the base of the bird, just above the lower diagonal branch, turns out to have been a leaf. I think this longer, leaner profile is inconsistent with Pileated Woodpecker and consistent with Ivory-billed Woodpecker, and not just because of the neck, the feature that was most suggestive to many who viewed the original capture. I’ve seen a lot of Pileateds and have looked at countless images online, and nothing about this better-resolved silhouette suggests Pileated. The remnant clips from the 1935 Ivory-billed Woodpecker film may be illuminating in terms of neck and body shape.

The silhouette in the November 30, 2009 capture, which was the first suggestive image we made public, is not as compelling as the one in the image shown above, but the capture shows three apparent ivorybill field marks – a black crest, white on the lower part of the bird, and a large, light-colored bill. In this case, the processing provides additional information about these apparent field marks. The bird also appears to be larger than a Pileated Woodpecker. The basics of all these issues are addressed in Frank’s original discussion of this capture.

To reiterate, I am not in possession of the original frame that follows the capture. It was probably lost after Frank’s passing, so I used two crops for the first composite, one showing the suspected ivorybill and the other, the subsequent frame. The crop of the empty frame was otherwise unaltered, but the one with the bird had the brightness and contrast adjusted. The output differed slightly between the “difference” version and the “subtraction” version, something I did not observe when working with unprocessed images. The difference, however, appears to be limited to background features and not the bird.

Remember that this capture was obtained from a spot where I’d had a sighting of a large woodpecker with a lot of white on the wings on the 25th . Both Frank and I heard the wingbeats, which were loud and distinctive. This was a rare instance in which a bird appeared to have been brought in by a double knock series. We’d also had an auditory encounter about 300 yards away on the morning of the 24th, while staking out the cavities in the willows shown above.

The first image shown below is the original capture with the red box around the bird. The crops appear as a pair of images. The first shows the bird, and the second is the subsequent frame with the bird absent. Those are followed by the difference and subtraction composites. More discussion after the images.

 

 

 

 

 

As I read this imagery, I think it suggests that the apparent white saddle is part of the bird, not light leaking through or an intervening object; indeed, the intervening branch is revealed in the ghosted images, with the body of the bird still visible behind it. That said, this may be the most ambiguous aspect. The treatment also highlights the presence of the crest and shows it is part of the bird; there is no red in the original; if any red were present, it should be at least faintly visible at this range and under these conditions. This interpretation is based both on the color in the background and on a Pileated captured perhaps six feet farther from the camera during this deployment (in an overexposed image included in Frank’s original analysis).

Most important of all is the fact that both the difference and subtracted versions confirm that the apparent very large bill (which appears to be light-colored in the original picture) is indeed a bill and not some other object. Even allowing for some motion blur, the bill is disproportionately large and therefore inconsistent with Pileated Woodpecker. Indeed, all discernible features in this photograph are consistent with female Ivory-billed Woodpecker and nothing else. I have always believed this picture showed an ivorybill. Based on these composites, I am now firmly convinced that it does.

I also tried creating a composite combining the capture, which was taken in the late afternoon of November 30, 2009, with another frame taken in late morning on the following day. The results are somewhat less distinct but the same elements are still apparent.

 

Finally, I tried this approach with the images discussed in the previous post. The results of this effort were somewhat less satisfactory. I assume because the originals are lower resolution and therefore contain fewer pixels. Lighting conditions may also be a factor.

This capture offers a lot less to work with. The Reconyx jpegs are 2048 x 1536 or 3 megapixels, while the Plotwatchers are 1280 x 720 or less than 1 megapixel.

I was unable to find additional specifications for the Reconyx cams, but the folks at Day 6 Outdoors were kind enough to provide them for the Plotwatcher. Per Day 6, the sensor is .25″ (which is smaller than most cell phone cameras); the focal length is 3.5 mm (which I think translates to the equivalent of an ~20 mm lens on a full frame or 35 mm film camera); and the aperture is f/2.6 (apparently the equivalent of ~f/16).

Nevertheless, I experimented with using both the original captures and versions enlarged using Topaz A.I. Gigapixel. I applied the same process to the squirrel capture from a few weeks earlier, which was taken under better lighting conditions. The relevant images and discussion are below, starting with an enhanced version of the original capture with an arrow pointing to the object of interest. Remember that the silhouette that resembles the head and neck of a woodpecker is background vegetation. The object of interest is the small bit of black and white below it.

 

As mentioned, I’m less confident about interpreting the results for this image, since so much less detail can be gleaned. Unlike the other captures, the subtraction or ghosting does not reveal a clear outline, and aspects of the object which are distinct when moving from frame to frame are obscured in this treatment. Also note the near absence of difference between the preceding and following frames.

In the enhanced iteration, a little more of the outline of the putative IBWO may be visible. I suspect that the reason the white saddle does not appear uniform in this one is due to pixels and that the dark patch below the bright white band is consistent between images because the foreground and background pixels match, not because they’re the same. This explains why the bottom part of the saddle, where the wings meet, is also white. In other words, these are the places where the object was in front of darker pixels. That’s my guess based on shifting back and forth between the relevant frame and the ones before and after. In addition, the white dots above the “saddle” may represent dorsal stripes.

Things change slightly when using imagery from different days. I’m only using the enhanced versions here, but they again strongly suggest that the white saddle is part of the object, not the background. The second frame is the one that follows the squirrel capture discussed below.

 

The squirrel capture may provide some additional insights into the process’s limitations with lower resolution images. The squirrel, which is clearly visible in the original image, shows up as a narrow strip that’s easily missed if you don’t know it’s there. The second version is a composite using images processed through Gigapixel A.I.

 

 

Weather and lighting conditions differed considerably between the two days in question. The camera was pointed in an approximately easterly direction, probably more ENE or NNE; lighting conditions may account for the fact that this image is a little lighter and some small differences are more apparent from this pair of captures. The weather at the nearest station at the time of the squirrel capture was fair with little to no wind; whereas the weather for the putative ivorybill capture, which was taken in the afternoon, was intermittently stormy with winds probably around 10 mph. Under stormy conditions with foliage moving in the wind, there should be more variation between images, not less, so available light seems a likely factor perhaps in combination with number of pixels.

Thus, I’m not sure how much this process adds when it comes to interpreting the most recent capture and how useful it might be with others from Plotwatcher trail cams. (The two older images were taken with a color Reconyx.) But I hope that the cameras are now deployed in such a way that enhancement and differentiating won’t be necessary.

While the approach does not reveal much when it comes to the new image, I think it is dispositive with regard to the old ones. Of course, I make no claims to expertise in forensic image analysis or the technical aspects of image processing, so I am open to being corrected if any aspects of my analysis are flawed.

Like most searchers, I have tended to focus on whether the evidence is sufficient and have seldom thought about what obtaining conclusive documentation might imply. If the two images from the old search area are ivorybills, a number of questions emerge. So let’s assume (or assume arguendo if you are unpersuaded) that these images indeed show Ivory-billed Woodpeckers:

As an initial observation, if I am right about the two captures, I think it becomes overwhelmingly likely that the apparent bill protruding from the cavity in the background of the neckbird image  also belongs to an ivorybill, so it seems probable that least two birds were present in the area in 2009-2010. This is consistent with what six of us heard during an auditory encounter in January 2010. One of Frank’s sightings involved three birds. (He was accompanied by the landowners’ teenaged grandsons at the time.) This sighting suggests that breeding might have taken place in the area.

The habitat in the immediate vicinity of the camera trap deployments is not what has been thought of as having much potential; the quality is even lower than I realized at the time. I knew a lot less about forest ecology and conditions in 2009, and while I certainly recognized the habitat as not “optimal” back then, I think I overestimated and perhaps romanticized the overall quality.

Both captures come from within 50 yards of a bean field. The woods in the immediate vicinity did have a number of large trees, and there are good sized cypresses in the area, but the parcel and the neighboring ones (including the one that was clearcut) are not particularly old. Back then someone indicated they’d been cut in the early 1960s.

The site of the earlier trail cam pic and our November auditory encounter is .6 miles from a large parcel of state land that has some very mature forest and inaccessible areas. (The location of my November sighting and the second trail cam capture is approximately 300 yards farther east, away from the public land.) Several other large parcels of public land are within a few miles of the area, so it’s not exactly a suburban backyard. Nevertheless, it’s a far cry from the Singer Tract or our current search area for that matter.

It seems to me that if one accepts that a pair of ivorybills was present in this location in 2009, there’s no basis for doubting the landowner’s claim that birds had been present and using the area for a decade or so. It also supports the idea that audio obtained there included ivorybill kents and double knocks, which tends to validate audio captured elsewhere – Arkansas, Florida, South Carolina, and our current search area.

How does/would the confirmation of ivorybill survival, especially in such ostensibly low quality habitat, impact the assessment of other reports?

Why is that ivorybills are being reported in so many different places over the last two decades? Is it just more publicity, or is something else going on?

Why aren’t there more reports from the public and from experienced birders?

Why are they so hard to document?  Even if you read the Project Coyote trail cam captures in the most liberal possible way, there are no more than a handful of images that I think of as likely, out of well over 1,000,000.

Where does one look for them, especially if they are using habitat always thought of as unsuitable?

What is suitable habitat?

What kind of population is out there and how has it sustained itself for so long?

I’m sure there are more, and I don’t have good answers for most. I think the technical limitations of trail cams, scarcity, and wariness (even run-of-the-mill or somewhat overdeveloped wariness) are probably adequate to explain many of the documentation issues but perhaps not the relative paucity of sightings.

I hope to return to my planned posting schedule with the post on range in a week or two and the one on evidence a couple of weeks after that; however, I’ve been looking at composites created from the Reconyx images discussed here. I think the results illuminating with respect to size. This post is already long, so rather than include them here, I will likely do a follow-up examining those images before turning to more general ivorybill-related topics.