Trip Report, March 5-17, 2019


The following trip report is mostly extracted from a post for members of the search team.

I was in the field from March 5-17; others were around before and after. Thanks to the whole team and a couple of guests for their hard work and contributions in the field this trip. We completed the swap out of recording devices in three days, which left a lot of field time afterwards. We were very fortunate in that only one unit was tampered with and only a couple malfunctioned. This is a very low rate of loss for these units.

We continue to have possible encounters in the area, perhaps at a higher rate than in past seasons, though the number of potential observers and time spent in the area has increased this year. And we have gotten some very preliminary results from the first round of deployments.

In addition to the audio deployments, we’re focused on obtaining DNA this season and have been refining the protocol for doing so. On this trip we collected samples from a couple of different forms of feeding sign, one I think is more promising than the other.

Here’s the basic protocol: collect a small quantity of material from places where a woodpecker’s tongue may have been; place it in a vial containing buffer and seal. With luck, genetic material can be obtained from these surfaces, and we can rule in or rule out ivorybill as the source of some kinds of feeding sign.

We also plan to collect samples from the most promising cavities. And are evaluating them following Cornell’s criteria. Cavities are graded:

A: very large cavity in size range of IBWO with irregular oval or rectangular shape (4.0–4.75in [10.2–12.1cm] wide and 5.0– 5.75in [12.7–14.6cm] tall);

B:  cavity larger than typical PIWO cavity but shape is fairly regular, nearly perfect round or oval; or, cavity of irregular shape and within upper size range for PIWO, and lower size range for IBWO (3.5in x 3.7in or [8.8cm x 9.5cm] large PIWO and 4.0in x 5.0in [10.1cm x 12.8cm] small IBWO);

C:  cavity of fairly regular shape, nearly perfect oval or round, in the upper size range for PIWO and lower size range for IBWO. Same dimensions as for B.

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Ivory-billed Woodpecker Cavity (1935 Nest)
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Typical Pileated Woodpecker Cavity

Here are some promising cavities (I’d grade all of them A or high B) I found last trip, plus some we know are being used by other species. I found more cavities this trip than I ever have in the past, mostly because I was paying attention. There’ll be some explanation in the captions. The truth is, no one really knows about cavities; I’ve seen a lot of variation in what PIWOs do; so a lot of this is speculation. I do think scaling or suggestive feeding sign on a tree with a cavity in it may be an indicator, including that the cavity is a former nest.

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Promising cavity, apparently recent

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Promising cavity with a little fresh scaling; however, there were Wood Ducks perched in this tree, which suggests that it may no longer be active.


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Cavities are harder to spot after leaf out. This one looks fairly fresh.

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Older large cavity in cypress stub.

It can be a tough call. The first pair of cavities shown below is being used (and was likely excavated by) Red-bellied Woodpeckers. The size is deceptively large, but the small diameter of the high limb is an indicator.

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The intriguing cavity below was being used as a PIWO roost but would probably have been graded A for its large size and irregular shape. There’s a second, possibly connected, cavity slightly higher and to the the left. Both are oddly shaped. The snag is severely decayed. But again, we have very limited information, so there’s no way to know whether IBWOs might avoid badly decayed snags.

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Regarding feeding sign, extensive scaling on boles, especially of mature trees with tight bark, seems likeliest for Ivory-billed Woodpecker work. Hickories are the highest priority within this category, and we have only found a few such trees over the years. Extensively scaled sweet gums, like the one shown, are worth noting too. A second category, involving smaller sweet gums and branches, is also intriguing. Ambrosia beetles are the prey species involved in this work, which involves extensive stripping and targeted digs into the insect chambers.

In all cases, it’s important to distinguish scaling from shallow excavation with associated bark removal.

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Suspected IBWO hickory chips

The appearance of this work is distinctive. The bark is removed cleanly, and there’s almost no damage to the underlying wood, except for expansion of the exit tunnels on the surface. We hope that DNA can be extracted from these tunnels and that the scaling shown in the first image is fresh enough to be a good candidate. Based on the life-cycle of the beetles involved, I suspect this work is likelier to be found in the latter part of spring and through summer, but keep your eyes open anyway.

We’re finding that Pileateds also feed on hickories and begin by removing bark. They go about it in a different way, however, excavating through the bark and into the sapwood. The appearance of Pileated work on hickories is similar but somewhat different. It tends to be patchier, without less extensive and contiguous bark removal. The chips are smaller, a mix of bark and sapwood, and the appearance of the wood in the areas where bark has been removed is distinctly different, as in the images below.

Extensive scaling on boles of other species is also noteworthy and may have DNA collection potential. There’s more room for overlap between what IBWO and what PIWO might be able to do, since the properties of hickory bark are unique. Look for extensiveness, large to enormous chips, and lack of damage to the underlying wood.

The final category involves sweet gum saplings and small to medium-sized limbs. I have found this distinctive appearing work in only two years, in a small cluster in 2015 and in a single example this season. The bark is extensively, indeed almost entirely, stripped. Chips on the ground should be large. Leaves should be still attached. The beetles’ brood chambers should have been vigorously attacked, and you may see superficial horizontal scratches in the sapwood (not the deeper grooves that used to be mistakenly ascribed to IBWO).

This was a longer trip than usual, and I was wiped out when I got home. We will be returning at the end of April to collect the units. This will mark the end of the deployments for this season, though we will continue to work with the trail cams, with a couple transferred to new locations. I’m hoping to have a guest post from a team member before the next trip.


Trip Report: February 2019, Multiple Units Deployed

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.

Ivorybill excavation in a sugar berry, from Tanner’s dissertation. Courtesy of the Division of Rare and Manuscript Collections, Cornell University Library

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.

Unusual cavity in sweet gum, with scaling.


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.


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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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 . . .

 


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.)

IMG_4195

Suspected Ivory-billed Woodpecker

rotatedcomposite

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.

IMG_2735-1

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.

 

 

 

 

 

imgp3505

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.

IMG_4399

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.

 


A Tantalizing Trail Cam Capture

Best laid plans . . . I’m pushing back the posts on historic range and evidence but hope to get to them soon.

In going through some of the remaining unexamined images from past trail cam deployments, Geoffrey McMullan came across an intriguing image. He sent me the file for the entire day without indicating where the image was located or what interested him about it. Reviewing cards is challenging; it’s tedious, while demanding focus and attention to very subtle changes. It can be easy to overlook hits of any kind. Nevertheless, this particular frame leapt out at me immediately, even though the object involved is indistinct and is only present in a single frame (more on that later).

I’ll begin by sharing and discussing the image, before and after stills, a time lapse video, and some additional captures comparing other animals with what’s shown in the frame. I’ll follow that with some of the discussion that has taken place among the active searchers in our group and some of the biologists who are advising us. Matt Courtman suggested that everyone on our email list give three reasons they like the image for ivorybill and three counterarguments. Not everyone followed the suggested format, but I’ll draw on those emails as well. I’m hoping this will give you some insights into our process and also give you some additional ways of looking at the image, which I believe to be a picture an Ivory-billed Woodpecker, even as I recognize that it isn’t nearly good enough to stand as proof.

I’ve done my best to present this material in a clear and careful manner. This is not an image that lends itself to immediate, easy interpretation, as some of the discussion reveals. At the same time, a lot can be gleaned from a close, careful look at the raw image, and the preceding and following frames. The various enhancements and comparison captures provide additional context.

A further caveat: I write this blog to maintain a log of our efforts and to share our results with readers on an ongoing basis, in an honest and transparent manner. As with any scientific endeavor, our search is in a constant state of flux. Everything is subject to change and reappraisal based on the evidence. We offer this image with that as background. Most of us believe subjectively that we have found an area that is used by Ivory-billed Woodpeckers, at least periodically. We all recognize that we do not have enough objective “proof” to “convince” third-parties that this is so. The subject image, so far, is just an intriguing part of the mosaic. It’s up to you to decide whether it moves the needle toward “proof” in your mind.

The image was captured on July 12, 2017. The target tree is a hickory that lost its top in a storm in March of that year. And we’ve had a camera aimed at it ever since. This is in area where we’ve found extensive scaling on hickories over the years and where we’ve had a number of auditory encounters. It is within the same contiguous forested area, several miles from the site of the March 2017 recordings. While squirrels are frequently captured on the target stub, there have been few woodpecker hits, and there was no obvious foraging sign on the trunk when I last visited in June.

Perhaps the most informative way to view the image is to step through the time lapse video frame by frame and compare the before, during, and after images. (You may have to download the clip to do this.) This will help clarify what’s object and what’s background. If you’re having trouble downloading the clip (and associated comparison clip), contact me, and I will share the files via Dropbox. I encourage you to click on the individual still frames to see larger, zoomable versions.

Here are two versions the relevant capture, one in its original, unprocessed form and another with a Luminar vividness filter applied, sandwiched between unprocessed captures from 20 seconds before and 20 seconds after. The arrow is pointed at the object of interest.

 

 

 

 

 

 

 

 

 

 

 

 

Here’s the time lapse video clip.

 

 

 

Here is a version of the still, resized using Topaz A.I. Gigapixel, an automated, artificial intelligence-based, image enhancement program. Following that are two enhancements, and a detail therefrom, made using another processor, Let’s Enhance. Both of these programs are automated, so except for selecting enlargement percentage and general processing parameters, I had no influence on the resulting images. Note that the prominent silhouette, which suggests a woodpecker’s head and neck, is blurred, background foliage, not part of the object. Assuming that the object itself is an ivorybill, I think the capture suggests the bird is angled slightly away from the camera, with head and neck inclined to the right.

 

 

 

Edited to add: A significant number of readers have misinterpreted the image, despite my explanation. To reiterate, the somewhat woodpecker head and neck-ish silhouette is background vegetation. The object’s head and neck are not visible. This detail, scaled up as much as possible, should be helpful, despite the loss of resolution.

Detail of Enhanced Detail 7:12:17_output (1)

 

Next are a squirrel and a presumed Red-bellied Woodpecker (9-11″ including head and tail) captured on a different day. They are included for scale. Both are a little lower on the trunk and are therefore closer to the camera. The captures are followed by a 50-frame Quicktime clip showing both the smaller woodpecker (suspected RBWO) and some squirrel activity. The comparison suggests that the object, which appears to be perched in typical woodpecker fashion, is too big to be a Red-headed Woodpecker (8.3-9.8″ including head and tail) and is slightly larger and more substantial than the head and body of an Eastern gray squirrel (9.1-12″). No tail, head, or neck is discernible, so the size of the object is in the appropriate range for an ivorybill body. (Total length is given as 19-21″ with tail at 5.5-6.7″ and bill at 2.3-2.9″) More discussion, including my responses (in italics) to some questions and comments (in bold and italics), is below.

 

 

 

 

An ornithologist wrote:

. . . I have tried every possible way to call that something other than ibwo but I can’t make it into anything else. The general impression of size and shape and even posture / body position relative to the tree is spot on.

And then in response to my explanation about the foliage that had caused some confusion:

I was seeing body only, folded wings white patch.

Early on, I had the following exchange with another biologist and ivorybill researcher:

Interesting. First, as I said before, I am no expert on trail cam photos like these. It looks like a black and white object for sure, with white on the bottom, but to my eye it is not possible to determine what kind of object it is. For sure, a bird would make a lot of sense. And if it is a bird, given the location, and pose on the trunk, a woodpecker would make a lot of sense. I am not sure if I see white at the top of the object as well?

How big is the tree that the object is sitting on, and is that scaling on the other side of the tree or remnants from when a branch that broke off? Have you seen bark scaling in that neighborhood?

I replied:

I’m pretty sure that it’s a bird and therefore a woodpecker. 

I think I see a white saddle and possibly a dorsal stripe. I also think it is too big to be a Red-headed, based on the squirrel and on a smaller woodpecker that’s on the trunk in another frame from another day; I’ll have to find that image.

The tree is a large hickory stub. What looks like scaling is where bark came off when the top fell. It is in an area that has had a good concentration of hickory scaling over the years.

If you have software that enables you to step through it frame by frame, the movie clip can be very informative. Flip Player is an easy one to use.

The response:

Thanks. I just looked at the entire series step by step with Quicktime and it is very intriguing. One question: could some of the white (or all of it) actually be sky in the background? The other frames show sky in the same location. I am not saying that it is, just trying to rule out possibilities.

My answer (another person raised a similar question):

I don’t think so. To my eyes, it’s pretty clear that the white is on an intervening object. I think the white on the object actually covers some of the dark area (as well as the lighter patch) behind it in the preceding and following frames.

And the conclusion:

Good. It is a very intriguing picture.

There was also this exchange with a consulting biologist:

Thanks Mark, well at least I see something here that should be encouraging to all.
Still, I’ve seen reconyx images of what ended up being squirrels that really had me going, where white seemed to be in the “right” places, but then a subsequent image would show a clear squirrel.  Those were black-and-white images and this of course is color, but unfortunately only one image in this series shows something.  
Thanks for sharing as always,

I replied:

If it’s okay with you, I may include a version of the comment in the blog, anonymously of course. 

One quick response, there are lots of captures of squirrels on the stub, but none from that day, based on several runs through the footage. In my experience, it’s extremely rare to see a squirrel in a single frame (20 second intervals) and not in any others. Also, none of the squirrel hits look remotely similar or show black and white coloration. I’ve now viewed several hundred thousand frames from these cameras. 

I can’t prove a negative, but I’d bet my bottom dollar that it’s not a squirrel.

Similarly, and while no one has raised it, I think partially leucistic PIWO can be rejected; I’ve spent a lot of time in the area and have never seen one, and all PIWOs captured on this trail cam and others nearby have been normal.

The rejoinder:

Sure, no problem.  But let me add the following.  

What are the chances of a large woodpecker kind of critter showing up all of sudden in one frame and no sign that it either flew in or left or was in view beyond the one frame 20 seconds or anytime later.  

An alternative could be some other sort of critter ( apparently larger than gray squirrel, perhaps fox squirrel, possibly raccoon) that worked up from the ground up the tree and then went back down out of view of the reconciliation.

As you said can’t be sure this is even a woodpecker or any other bird.

Beyond all that, still “interesting” but how many times…

I had one point of disagreement:

I mostly agree – with one quibble. It’s not unusual for birds to show up in a single frame and no others (the probable RBWO in the other clip, for example); it’s much rarer and (more difficult) for mammals to do so.

My bad for not deploying the camera closer to the target; in my own defense, I’ve only just started to get a handle on how to work with the cams. It was not my department until recently. I was a little concerned about distance with this deployment but not concerned enough . . . some auspicious timing here, since the image turned up while Tommy was servicing the cams.
Going forward, anything larger than a DOWO that turns up on target trees (though not in the background or flying by) should be identifiable.

My correspondent recognized the quibble as a fair point, and it bears repeating that there have been very few woodpecker hits on this tree, probably because it is very recently dead. This exchange also led me to suspect that some of my colleagues were thinking the background foliage was part of the object in question. The discussion ended with this observation:

You are right Mark, I was interpeting the background veg as looking like the neck and head, which really made me wonder why so faded. However, now we have a frame 33 of the Luneau Video situation.

Anyway, thanks for the re-orientation.

Another member of the group also mentioned Luneau, and the similarity is striking, although there’s no accompanying video, and this single capture seems to show more than the Luneau frame.

This exchange with another advisor came soon thereafter, although the initial comments were made based on thinking the foliage artifact was part of the object. My answers came after the clarification, and I’ve deleted the comments that pertain only to the foliage:
Positive impressions –

1) first the obvious, I can’t tell much from the original picture other than it is long and somewhat “thin” relative to more stocky animals. Based on the zoomed in picture, however, it is a live bird; I can see no way it was photo shopped or that it was placed there as a wooden (or otherwise) replicate. I think it is easy to dismiss any attempt at faking it.

Definitely no fakery here 😉

2) The zoomed in image is impressive, it certainly appears to have a white back (which is a slightly different color than the white of the sky next to it) and I see what appears to be two white stripes on the back as well. The comparison of a probable RBWO on the same tree is noteworthy and clearly shows the relative size of the bird in question.

I think the size comparison stands regardless.

Negative concerns –

1) Any of the above positive impressions may be a function of zooming in well beyond the camera’s ability to correctly interpret what’s really there.

Actually, I think that it’s somewhat more compelling unaltered, if you can toggle.

3) The only one frame concern ****** brought up . . . . . . while I don’t think this is a squirrel or mammal of any kind and I’m not at all concerned about this particular series (see below), I am puzzled that the bird in question would not have shown itself on other occasions as well. Are there any pictures of this tree with a PIWO on it? How many pictures (days) do you have images from this camera on this tree? Is the primary foraging area on the other side of the tree? I’m assuming you have several days in not a few weeks worth of pictures on this tree (?)

The camera has been there for over a year, and I’ve gone through countless images. No other suggestive hits. Lots of squirrels. I don’t recall specific PIWO hits on the target tree, although there may have been some, and I’m sure there were at least a few from the deployment. This is one of the targets that has no scaling on it as yet; visits from woodpeckers have been few. As with the RBWO, I suspect birds may be hitting the tree in an exploratory manner at this point and are not staying long.

Just FYI . . . .This is [not far] from where we saw the bird that I ended up thinking was a RHWO and that you weren’t quite so quick to give up on, closer to where I had the long neck and tail silhouette sighting after some ADKs.

An additional note about not concerned about this series and only one frame . . . . .I feel strongly that IBWOs are incredibly wary, much more than we have been assuming them to be. And as any resident bird, it knows its territory very well and that anything “new” or different in that territory could spook it. I hunt as you know, and can vouch that turkeys and waterfowl are often that way . . .one thing out of place from the normal and they leave . . . 

With that said, I wouldn’t be surprised, if this is an extremely wary IBW, that it knew something was not quite the same in the area and stayed on the far side of the tree on purpose  . . .  Even as I type it and re-read it, it sounds a little crazy but since I know about that level of wariness in other species I take it seriously. I know the discussions about wariness and “Tanner’s birds” etc but not sure birds now would act the same way as birds 60 – 80 years ago. If they are that wary, then that also has implications to where the camera is moved. It has to be close enough for a good picture but far hidden well enough to not spook the bird. (If you talk to Tommy or others about new deployment of the camera, my thoughts about how the wariness of this bird is pretty well known and doesn’t have to be anonymous).

I’ve wondered about this myself, and it seems like a pitfall when it comes to putting cameras very close to target trees. With time, however, I suspect birds would become habituated. It’s always a trade-off with these cams, and unfortunately, they have to be placed quite close to the targets.

Thanks for keeping me in the loop Mark – all in all, this has the most “real” field marks and most potential of anything I’ve seen.

I really do think it’s an IBWO . . . it’s at least more cause for optimism and grounds for staying with the trail cam strategy. As I’ve said, I think we’re finally in a position to do it right.

Here’s the response:

Thanks for more clarification Mark – yes I did toggle back and forth, now that I’m not so worried about what I thought was head, neck and bill, the unaltered is more intriguing.

Good to know its been there a year, I agree that birds will get used to it being there over time. The picture has July 17 2017 along the bottom, is that correct or is it July 2018?

I also forgot that this was a tree that you were interested in before any scaling started . . . .that’s pretty exciting and would explain my other concerns about infrequent use and no PIWO use. Pretty exciting in that (if a 2018 picture) the best is yet to come for woodpeckers. Regardless of IBWO, keeping a camera on this tree and having a sequence that shows which woodpeckers use tree, when and how (assuming there are differences based on tightness of bark etc) would be cool from that area.

Frankly, as I was looking at the picture(s), I thought a few times “Damn, I think he got it” . . . . . . Thanks again,

I replied:

The picture is indeed from 2017. But there’s no scaling on it as yet, so it’s worth staying with.

I hope these exchanges help to illustrate some additional challenges related to trail cams, while revealing something about the review process. I think the object in question is an Ivory-billed Woodpecker; so do some of my associates. It’s not proof beyond a reasonable doubt, but it is an encouraging and suggestive piece of evidence.

 


Updated – Emerald Ash Borers and Blonding: A Large Body of Bark Scaling Evidence Tends to Rule Out Pileated Woodpecker as The Source of Scaling on Hickories

A couple of initial housekeeping notes: I still plan to do a second, more conceptual post on ivorybill evidence, one on historic range, and possibly another on non-IBWO trail cam imagery. Look for those over the course of the summer. I thought this subject should take precedence and have changed plans accordingly. The photographs (other than my own), which I’m including in the largest possible sizes, are courtesy of bugwood.org (under a Creative Commons License) and Patowmack the trickster.

Thanks to John Kearvell for inspiring me to pursue this subject.

Summary

The emerald ash borer or EAB (Agrilus planipennis) is an invasive Buprestid beetle. The first known North American outbreak was near Detroit, Michigan in 2002. Since that time, the species has spread to 33 states and three Canadian provinces.

Bark scaling, especially by Pileated Woodpeckers (Dryocopus pileatus), is one reliable indicator of EAB infestation, and Pileated Woodpecker populations appear to increase as a result of outbreaks. Thus, there is now a large body of data on bark scaling that was not previously available for comparison with suspected Ivory-billed Woodpecker (Campephilus principalis) work.

All of the numerous examples of white or green ash (Fraxinus americana or pennsylvanica) scaling by Pileated Woodpeckers (and presumably smaller woodpecker species as well) found online show “blonding” or removal of bark in layers. This may be due to anatomical limitations that preclude Pileated Woodpeckers from removing thick, tight bark in large pieces. Suspected Ivory-billed Woodpecker work on hickories – which have harder, tougher, tighter bark than ash – shows no trace of blonding or gradual removal. I think this excludes Pileated Woodpecker as the source of the hickory scaling.

Introduction: The Emerald Ash Borer

EABs are believed to have arrived in North America in packing materials. The first outbreak began near Detroit in 2002, and the species has spread rapidly since then, decimating native ashes wherever it goes. All indications are that this invasive insect will have an impact akin to that of Dutch elm disease or chestnut blight, concerted quarantine efforts notwithstanding. Because EABs were a recent arrival and had not been well-studied during the first decade of the 2000s, their relevance to the issue of bark scaling does not appear to have been recognized by the formal searches that were conducted during that period.

While the invasion’s impact has already been devastating, EAB larvae are attractive to woodpeckers, especially Pileated Woodpeckers (Koenig and Liebhold, 2017), and bark scaling is one of the most obvious symptoms of infestation. (This attractiveness may have future implications for any surviving ivorybills as the EAB expands its range.)

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Table from “A decade of emerald ash borer effects on regional woodpecker and nuthatch populations”, Koenig, W.D. & Liebhold, A.M. Biol Invasions (2017) 19: 2029. https://doi.org/10.1007/s10530-017-1411-7

Unlike many bole dwelling Cerambycidae, such as Hesperandra politawhich spend the bulk of their lifecycle in the heartwood and do minimal damage to the cambium, EAB larvae live, feed, and pupate just beneath the bark, eventually destroying the cambium. This causes the bark to fracture and sometimes to slough off by itself. In the very dramatic example shown below, I suspect that woodpeckers were involved in most, if not all, of the bark removal but only reached the sapwood well after the bark had started to loosen, fracture, and perhaps fall off on its own. Nevertheless, there are still signs of layered removal on the edges of the scaled/sloughed area.

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EAB Larvae. Photo by Kenneth R. Law, USDA APHIS PPQ, Bugwood.org

 

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Tunnels and bark fracturing caused by EAB infestation. Photo by Joseph OBrien, USDA Forest Service, Bugwood.org

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Entire cambium destroyed by feeding. Photo by Daniel Herms, The Ohio State University, Bugwood.org

Blonding

When I started researching this subject, I was unaware that the term blonding had been applied to woodpecker work in pursuit of EABs, but it has become a widely-used (and apt) descriptive. It refers to the appearance of ash trees or parts thereof, after woodpeckers have started removing the outer bark in pursuit of EAB larvae and pupae. The process of reaching the sapwood appears to be a slow one, and after examining hundreds of images showing of bark scaling on ash trees, I have been unable to find a single example that was devoid of blonding, even when very extensive work was involved.

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Art Wagner, USDA – APHIS, Bugwood.org Damage resulting from woodpeckers searching for a meal on an infested tree

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Kenneth R. Law, USDA APHIS PPQ, Bugwood.org Heavily infested Ash tree with Emerald Ash Borer and woodpecker activity in evidence. Some galleries exposed.

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Kenneth R. Law, USDA APHIS PPQ, Bugwood.org

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Steven Katovich, USDA Forest Service, Bugwood.org Outer bark removed by woodpecker activity

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Steven Katovich, USDA Forest Service, Bugwood.org

 

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Dramatic example of presumed Pileated Woodpecker foraging in pursuit of emerald ash borers. Note remaining traces of blonding on the edges and blonding on trees in the background. Credit: Patowmack the Trickster https://patowmacktrickster.com

Patowmack the Trickster’s photo is the most extensive example of apparent Pileated Woodpecker scaling on an EAB infested tree that I’ve been able to find. The tree appears to be fairly long dead – based on the extent of the superficial excavation (tunnels are no longer distinct), the apparent fracture in the trunk at the center of the frame, and on the apparent separation of the bark from the sapwood that’s most distinct on the lower right edge of the scaled surface. While the extent of this work is impressive, I’d suspect PIWO even in potential ivorybill habitat – based on the appearance of the surface, the state of decay and seeming looseness of the bark, and the blonding, which is most evident at the top and at the lower left.

While smaller woodpeckers are responsible for some ash blonding, Pileated Woodpeckers are likely the primary source, especially when the work is as extensive as in the examples shown above. Images of Pileated Woodpeckers on blonded surfaces are considerably easier to find than ones involving other species. This brief video catches a PIWO in the act, on an extensively blonded tree, and points to the difficulty PIWOs face when scaling tight, thick bark.

Blonding on Other Tree Species

I have found blonding or its equivalent on a number of other tree species, so it is not exclusively related to any characteristics of ash bark. Rather, I think it is a function of Pileated Woodpecker anatomy. I have seen this on limbs, including sweet gum (Liquidambar styraciflua) limbs, in our search area and have described it as a “layered” appearance.

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Known Pileated Woodpecker scaling on a medium-sized sweet gum limb with evidence of layered bark removal or blonding.

It may be possible for Pileated Woodpeckers to remove tight bark from small to medium branches without leaving traces of blonding, especially if the bark is weakened or it comes from a species (like sweet gum) that is relatively soft and thin. Removing thick bark from mature boles is something else again, and I suspect that even when bark has loosened considerably, traces of blonding will often be visible when the work is done by Pileated Woodpeckers.

I have found one extreme example of suspected, extensive PIWO blonding on a bole in Louisiana. I think the tree involved is a sweet gum, but if it is an ash, it would be from a location well outside the range of the EAB today, let alone in 2011 when the tree was found. While blonding is easily visible on the trunk, it can also be recognized by examining bark chips.

 

 

 

I have seen the equivalent of blonding on loblolly pines (Pinus taeda) in the southeast and on softwoods in Westchester County, New York. The bark of most conifers is weaker and less tightly adhering than that of most hardwoods, and it typically becomes easy to scale far more rapidly. This is why I long since abandoned the idea that softwood scaling  might be suggestive of ivorybill, unless it involves extensive work on multiple large trees.

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Loblolly Pine with blonding, South Carolina 2011

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Blonding on dead softwood, Westchester County, NY, 2011

I have also found it on live and dead hardwoods in Westchester County, NY. The first pair of images below, which I’ve posted previously, shows fresh, known Pileated Woodpecker work on a Norway maple (Acer platanoides) in my yard. (I saw the bird.) The second pair is from a local park. The snag, which I believe is a large sassafras (Sassafras albidum), appeared to be fairly long dead.

 

 

 

 

 

 

 

Ash Bark v. Hickory Bark

Ash bark resembles that of bitternut and pignut hickories (Carya cordifromis and Carya glabra), so much so that an arborist mistook the pignut that grows outside my office window for an ash and advised me to monitor it for EABs. Testing bark hardness with a fingernail is one way to avoid confusion. Ash bark feels corky, whereas hickory bark is extremely hard. Last year, I wrote an in-depth post on the characteristics of hickory bark and the reasons it is exceptionally difficult to remove. I won’t recapitulate it here, except to say that hickory bark is considerably harder and stronger than that of virtually any other genus. It is also tighter when trees are dormant or dead, as these reposted tables suggest.

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The values shown are for shagbark hickory (Carya ovata), which is slightly stronger, tougher and tighter than bitternut or pignut. While white and green ash bark is considerably stronger and tougher than sweet gum and white ash bark is harder to remove from dead trees, neither species comes close to hickory in any category, except bark tightness when sap is flowing.

I suspect that the extreme strength and toughness of bitternut and pignut hickory bark renders it impervious to blonding. Certain pignuts may be a partial exception, as the outermost bark layer on that species is sometimes slightly subject to flaking. I removed the outer layer of bark from the pignut hickory mentioned above to illustrate; the inner layer is very hard and tight.

 

 

Our observations thus far suggest that Pileated Woodpeckers can excavate through hickory bark, leaving behind small pieces, and can remove narrow strips of hickory bark from already scaled areas.

 

We have found nothing to indicate that Pileateds can go straight from outer bark to sapwood and remove the hand-sized chunks we’ve found under the scaled hickories in the search area.

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Detail of the hickory shown on the home page. Note the absence of blonding on the edges. Also note possible superficial bill marks on the lower right, a detail I had missed, and the targeted digging into the exit tunnels.

Conclusion

All of this strongly supports the hypothesis that Pileated Woodpeckers are incapable of scaling hickories in the manner that I believe to be characteristic of Ivory-billed Woodpecker. I’d further argue that the absence of blonding on boles of any hardwood species may be suggestive of ivorybill, provided the bark is thick (over ~.5″) and tight. This is not to suggest that ivorybill work never shows traces of blonding. Though the image quality is poor, Tanner’s Plate 8 may show it.

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Something similar to blonding is visible in examples of scaling by other Campephilus species. Thus, an absence of blonding on scaled hickory boles may be a basis for rejecting Pileated altogether and may be suggestive of ivorybill when other tree species are involved.

Update

On a recent visit to a park in Orange County, New York, I found many EAB infested, blonded ash trees. I only had my iPhone with me, but I took some close ups and one shot of the chips on the ground. I also collected some chips and photographed them at home. One of these chips was particularly interesting; while it include some of the outer bark, most of it was from an intermediate layer, further illustrating how the bark is flaked off and that multiple events of stripping are involved before the cambium is exposed.