To expand on some of the data included toward the end of the March trip report (which is worth reading in in conjunction with this post), I thought it would be informative to provide a season by season and sector by sector breakdown of the scaling I and others involved with Project Coyote have found since the spring of 2012. To do so, I’ve gone through my notes and photographs and have done my best to reconstruct the data collected. While not complete (I’m quite sure a good deal more scaling was found in Sector 3 during 2013-2014, for example), I think this breakdown is a fairly accurate reflection of what we’ve found over the years.
As discussed in previous posts, I think extensive scaling on hickory boles is the most compelling for Ivory-billed Woodpecker. Bark on this species is thick, dense, and usually remains very tight for a long time. Extensive scaling on sweet gum boles and oaks (upper boles and large branches) is second among work that I’ve found. Work on small boles, and higher and smaller branches is somewhat less compelling and is more significant for its abundance. Some of the high branch scaling and work on smaller boled sweet gums may well have been done by Pileated Woodpeckers (and possibly by Hairy Woodpeckers), but the abundance, the presence of large bark chips in many cases, the way it appears in clusters, and the fact that Pileateds scale infrequently suggest a different source for much of it.
I have excluded all work where squirrels are suspected but have counted one tree, a hickory found this year, on which the work could well have been that of a Hairy Woodpecker. Hairies do forage for Cerambycid beetles just under the bark, but they’re only capable of removing tight bark in small pieces; their work on hickories is perhaps more accurately described as excavation through the bark.
The trail cam images toward the end of this post are the best we have (out of many thousands of hours of coverage) showing how these species forage on suspected ivorybill feeding trees.
All trees were live or recently dead (twigs and sometimes leaves attached). All scaling was on live or recently dead wood.
Sweet Gum (Liquidambar styracifula)
Sector 1: 46
Sector 2: 8
Sector 3: 51
~15% had scaling on boles (a few of these were large trees). The majority of work was on crowns, including larger branches. Fallen trees were included when woodpecker involvement was evident and bark was tight.
Bitternut Hickory (Carya cordiformis)
Sector 1: 3
Sector 2: 4
Sector 3: 7
All trees were standing; scaling was on boles and was very extensive (the tree shown on the homepage is one example) with one exception from this year . Insect tunnels were visible in all examples. An additional hickory with a modest amount of high branch scaling was found in Sector 1 this year but was not counted for this analysis.
Oak (Quercus) spp.
Sector 1: 1
Sector 2: 4
Sector 3: 0
All oaks had scaling on large branches; one also had some on the bole. All oaks in Sector 2 were found in a single cluster.
We have some information on forest composition in Sector 3, and it appears that sweet gums make up approximately 19%, oaks upwards of 35%, and hickories somewhere under 10%. Sectors 1 and 2 may differ and be more varied in overall composition.
The overwhelming preference for sweet gums relative to their abundance stands out. The scaled oaks are a mix of species, one Nuttall’s, one willow, the others unidentified.
In Sector 3, I am treating the compact stretch from the location of Frank Wiley’s sighting last spring/downed sweet gum top where we had the camera trap to just south of our current deployment as a cluster. The estimate of 23 trees being found in this area is conservative. I have only found one instance of recent scaling north of the location of the downed limb/Frank’s 2015 sighting. The main cluster has been in the same vicinity this year and last, with additional work scattered around farther south. Two of the hickories are within 30 yards of each other, approximately half a mile from the cluster, and one was on the edge of the concentration.
It also may be significant to note that we found a cluster of old but intriguing cavities in the same vicinity as the Sector 3 concentration in 2013-2014. Most of these seem to have fallen. The difficulty we’re having finding active, suggestive cavities is vexing, and may be the most compelling reason to be skeptical about the presence of ivorybills in the area. At the same time, finding Pileated cavities is difficult, even in defended home ranges.
I’m treating Sector 1 as a single concentration; the vast majority of the work is on a natural levee where sweet gums are abundant. The entire area is considerably larger than the other clusters, but given the abundance and ease with which we’ve found sign there over the last five seasons, I think it constitutes one area of concentration.
In Sector 2, there was a small cluster in the area where I recorded putative kent calls in 2013, with work found in 2012 (spring and fall) and 2013. Because the area is small with open sight lines, I can be confident there has been no recent work there since late in 2013 (I last passed through it with Tom Foti back in March of this year.)
The sweet gum work Tom and I found on that day was perhaps half a mile north of this cluster, within 100 yards of the hickory on the homepage. The other hickories found in the 2013 and 2014 seasons were not far away, no more than 500 yards apart as the crow flies.
There’s obviously some bias here, since there’s a relationship between finding feeding sign in a given area and spending time there. Nevertheless, I have little doubt that the putative ivorybill work tends to be clustered. I also have little doubt about the strong preference for sweet gums, since I’m not looking at tree species when I look for scaling. The degree to which sweet gums are favored has only become clear over the last year or so.
Frank pointed out this data does not reflect most of the scaling that likely exists in relatively close proximity to the Sector 3 cluster but cannot be quantified because it is in an area we have intermittently visited due to inaccessibility. Only two or three examples are from this area, which has been visited a handful of times.
In late December 2014, I wrote what I’ve described as a speculative post titled, “Is There a Way to Recognize Ivory-billed Woodpecker Excavation? In that post, I relied on Tanner’s Plate 11,
a brief description from the monograph: “When Ivory-bills dig, they chisel into the sap and heartwood for borers like other woodpeckers, digging slightly conical holes that are usually circular in cross section (Plate 11)”, and online imagery showing the work of other Campephilus woodpeckers. Material found during my recent visits to Kroch library at Cornell lends some support to the ideas contained in that post, and so does T. Gilbert Pearson’s photograph of a tree that had been fed on by ivorybills.
The archival material includes additional images of ivorybill excavation and a considerably more detailed description by Tanner in a document prepared for the Cuban search in the 1980s. The passage includes somewhat more detail on bark scaling than is found elsewhere, but more importantly it describes ivorybill excavations as “hard to distinguish from similar digging by the Red-bellied Woodpecker”.
Courtesy of the Division of Rare and Manuscript Collections, Cornell University Library
This description may seem counterintuitive to some. Despite my own writing to the effect that ivorybill morphology may lead the species to dig less efficiently than pileateds and my references to targeted digging, I still had an underlying assumption that the size of the bird would correlate with the size of the dig and that ivorybill excavation would often resemble the familiar large furrows dug by PIWOs. While a couple of the holes in Plate 11 and in Pearson’s photograph may well involve the merging of more than one dig, it appears that ivorybill excavations are usually more targeted and that large furrows are not typical.
Also of interest for multiple reasons, including the observation of birds scaling very small limbs and of one feeding 5′ from the ground, are Tanner’s field notes from April 3rd, 1937.
I’ll let the remaining images of known and suspected ivorybill excavations speak for themselves and will conclude with a few from our search area that seem consistent with known ivorybill work. While I’m nowhere near as confident about this material as I am about scaling, I suspect that finding excavations that are consistent with what ivorybills are known to have done in conjunction with scaling is suggestive.
I hope this material will be useful for other searchers. All images from the Singer Tract below are courtesy of the Division of Rare and Manuscript Collections, Cornell University Library. Most of these images were published in Tanner’s dissertation but have not been widely disseminated.
And now some examples from our search area that resemble the existing images of known ivorybill excavation. This is not something I’ve focused on, so I’ve probably missed other examples.
There will be one or two more installments in this series, but the next post is likely to be a trip report, probably the last for this season.
Although it is thematically quite different, this series of posts is rooted in my recent reexamination of my feeding sign hypothesis that culminates here. It was also inspired by my recent and much closer look at Tanner and the Singer Tract, new insights gleaned from old material, and the input of others that shaped the previous post. My original plan was to make this entry the last in the previous series, but since it has grown to over 5,000 words and addresses different issues, I decided to break it in three and will post the next two installments soon.
I’ve been engaged in an extended dialog with a biologist who is familiar with all the Ivory-billed Woodpecker literature and knows Tanner’s writings specifically. Our back and forth is the primary reason for the long interval between the previous post and this one. This person provided some very important insights that will be included in these posts. At the same time, we have a few points of disagreement. In the interests of transparency and allowing readers to draw their own conclusions, these points of disagreement will be disclosed in the text.
Ivory-billed Woodpecker foraging behavior and diet and what separates this species from Pileated Woodpecker and other North American woodpeckers are issues that have been hotly contested for years. In my view, ivorybills could (and presumably do) forage on any species of tree in any decay condition. However, Campephilus anatomy is specialized, and the only quantitative, observational data that exist on what this species does while feeding young (Tanner 1942) suggest some specialization was in fact occurring at least at the Singer Tract from 1937 to 1939. The problem is that many of the prey items (specifically identified in Tanner and emphasized by others since Tanner’s study), even during breeding, do not seem to match up well with the foraging substrates documented by Tanner as most used by ivory-bills feeding young.
In my view, there are some discrepancies between what Tanner observed and reported and the physical evidence he collected during his study related to ivorybill feeding. I also think there may be discrepancies between Tanner’s observations and those of others from the Singer Tract. At least one thing is clear, Tanner’s observations and the photographic record differ markedly from some of his later recollections. In addition, the monograph itself is sometimes ambiguous, as is evidenced by the disagreements mentioned above. It should become clear that the ambiguity and occasional lack of clarity in Tanner’s monograph have led many, myself and my collaborator included, into misinterpretations. We hope that this series of posts will shed more light and clear up some of the ambiguities.
As most readers already know, Tanner’s observations were restricted to one (and the same) family group each of the three breeding seasons during his study. While a sample size of essentially one family group would normally be a serious constraint for comparing with other information, it is important to point out this information represents the only detailed information we have on prey, foraging behavior, and breeding success for ivory-bills, keeping in mind this family successfully fledged young each of these three years. So the data and information Tanner reported on is directly relevant for understanding what was important for successfully fledging young under the conditions found at the Singer Tract during the late 1930s, but as Tanner himself pointed out in his monograph “…the conclusions drawn from them will not necessarily apply to the species as it once was nor to individuals living in other areas.”
Regarding the observations of others on the Singer Tract, I’ll begin with what may have been the last sighting of the John’s Bayou male. In August 1941, George Bick saw three ivorybills feeding in an ash flat near Sharkey Road, quite likely between the bridges over John’s and Methiglum Bayous, south and west of the John’s Bayou home range as delineated by Tanner. This is the only area along Sharkey Road that Tanner listed as “Ash Flat” on his 1941 map.
According to Bick, “I immediately stopped the car and noticed two Ivory-billed Woodpeckers perched in two small ash trees about eight inches in diameter, having recently killed tops. Only one of the birds was carefully observed. A bright, white bill, flaming red crest, and large white wing patch were all clearly noted as the bird remained at the tree. The second bird in a similar ash tree was observed less carefully . . . [A third bird] flew from a dying water-oak tree ten inches in diameter which had only a few curled brown leaves. A stripped spot about six by eight inches and about seventy feet from the ground was present on the trunk of this tree. This is thought to be a spot where the birds had been feeding and to represent the characteristic Ivory-bill ‘sign.’ In the immediate area were many ash trees with dead tops. Much of the bark was stripped in patches of varying size. This may possibly be old Ivory-bill feeding grounds.”
Logging had taken a significant toll in the Singer Tract by the time of Bick’s sighting. It’s thus possible that the birds were foraging in a suboptimal area due to logging pressure. Nonetheless, it’s still worth pointing out that Bick’s observations were in habitat and on tree species where Tanner observed virtually no foraging activity during his study (which ended two years prior, in 1939; he had no feeding observations on water oaks and only one on an ash). It’s also worth pointing out that Bick made specific reference to sweet gums (what he called “red gums”) as being abundant elsewhere but absent from this location.
My collaborator suggested that Bick’s inference that this ash flat was an “old Ivory-bill feeding ground[s]” is questionable. He suggested that changes in hydrology due to logging may have led to an ash die-off. He also noted that this was Bick’s only observation during his six month stay in the Tract, indicating that he was either not looking hard for ivorybills and/or that ivorybills were not using the ash flat on a regular basis. He added another caveat: it is important to remember that Bick’s observation was in August, well after the breeding season when even Tanner assumed foraging behavior for Ivory-billed Woodpecker likely expanded to different habitats and tree species than used during the time they were feeding young at John’s Bayou.
It’s interesting to note that the last known roost, where Don Eckelberry and young Billy and Bobby Fought famously said goodnight to a lone female ivorybill in April 1944, was apparently located in the ash flat where Bick saw his birds (W. Barrow pers. comm.). Just a few months earlier, in December-January 1943-’44, Richard Pough found a lone female roosting in the heart of the John’s Bayou range, about a mile north and east. According to Pough, who was convinced she was the last ivorybill in the Tract, this bird only crossed the Bayou once “for a brief visit to some trees a few hundred feet west of it . . . confining its activities to an area of hardly more than one quarter of a square mile, within which there were an unusually large number of dying trees.”
In our most recent conversation, my contributor and I touched on the question of whether Bick’s birds (and presumably the one seen by Eckelberry and the Foughts) were from the John’s Bayou family group. Either way, it’s a potentially interesting wrinkle. If the birds did come from John’s Bayou, this points to a heavier use of the ash flat for a period of years than is suggested by the limited information about the family group after 1939. All other observations – Pough, Peterson, Tanner, and Baker – were in the heart of the John’s Bayou home range, and at least one of those birds was reliably present there until shortly before Eckelberry and the Foughts said goodnight. On the other hand, if Bick’s birds were a different family group, it suggests that more ivorybills were in the Singer Tract in 1941 than is commonly assumed. (It’s worth repeating that Peterson wrote that one ivorybill was seen in December 1946, and the last letter to Tanner directly related to the Singer Tract birds says that game warden Gus Willett saw a pair in November 1948 and mentions other reports from around that time.)
To return to the Bick report: all of the trees seem to be in the smallest of Tanner’s size classes, 3-12″ in diameter. This class comprised 75.1% of the forest but was the source of only 12.7% of Tanner’s feeding observations. Tanner believed that ivorybills prefer larger trees because they “have more dead and dying wood” but his own data on this are ambiguous, and what he characterized as large seems problematic. The assumption about older trees having more dead and dying wood may have been true around John’s Bayou during Tanner’s study, but this is by no means always the case – the pine forests of Florida, for example, where Allen and Kellogg found abundant feeding sign on young dead pines, which are more vulnerable to fire than mature trees. And as pointed out in the previous post, even in the Singer Tract, the Mack’s Bayou home range was mostly second growth, so forest composition there must have been quite different.
There are a couple of ways to interpret this data. It’s true that 87% of the feeding was “on trees that are over a foot in diameter”, but this is somewhat misleading. 13-24″ diameter trees are the second smallest size class. They hardly qualify as large and approaching senescence, yet they account for 49% of Tanner’s feeding observations. It’s also true that, relative to abundance, the Singer Tract ivorybills showed a strong preference for trees in the 25-36″ class, but the abundance/observation ratios for 13-24″ trees and over 36″ trees are nearly equal, with a slight preference for the smaller size class not the largest. Thus, I think it’s equally accurate to characterize the data as showing that over 60% of observed ivorybill foraging was on smaller trees, under 24″ diameter at breast height and to reiterate that the most often used feeding trees were in the second largest size category, not the largest. (Tanner pp. 43-45).
On the other hand, there’s a good argument that the data show Ivory-billed Woodpeckers foraged on trees in the 13-24” class at 2.6 times the availability, in the 25-36” class at 6.7 times the availability, and in the 36” plus class 2.57 times the availability; there were very few trees in this size class, most of them sweet gums and a few Nuttall’s oaks (Tanner pp. 43-45). Contrast this with the 3-12” class, when the trees were 5.9 times more available than used.
A few additional points should be added to the mix. The numbers discussed above are aggregates, and size preferences were not at all evenly distributed among tree species. Fully 20% of Tanner’s total observations involved sweet gums in the 13-24” class, the most fed upon type. On sweet gums, frequency and abundance ratios are similar for the 13-24” and 25”-36” classes (the latter is the second most fed upon type, comprising around 18% of Tanner’s total observations). For Nuttall’s oak, 13-24” and 25-36” trees were approximately equal in abundance, but Tanner observed considerably more frequent feeding on the larger class.
My collaborator argues that it is more important is to recognize that when combining the data on sweet gums and Nuttall’s oaks, they collectively comprised 31.4% of the total forest and 79.3% of the foraging observations. Trees within the 25-36” class made up 31% and trees within the 13-24” class made up 29% of all foraging observations. Almost all of the trees in the 25”-36” class (5.2%) were in fact sweet gum or Nuttall’s oak, but for trees in the 13-24” class (18.3%) only about 5% (or about a third) were of these two species. This further highlights what Tanner described as heaviest use on sweet gum and Nuttall’s oak for the John’s Bayou family group over all other available trees, and a disproportionately high use of the second largest size class relative to abundance. However, this documented use pattern was not to the total exclusion of other tree species or even the smallest size class available.
This last was a point of contention. I took issue with aggregating sweet gums and Nuttall’s oaks, since they grow and mature at different rates. In addition, I think it’s important to highlight the fact that 13-24″ sweet gums were the single most fed upon type both in terms of frequency of observations and ratio of observations to abundance (albeit it by a small margin). As I see it, this undercuts the misinterpretation of Tanner that ivorybills are ‘large tree specialists’, a misinterpretation I think Tanner invited when he wrote, “The reason for Ivory-bills feeding on the bigger trees is that large, old trees have more dead and dying wood. Young trees grow rapidly and are resistant to the attacks of insects and disease.” As trees ‘mature’ their growth slows and becomes less vigorous, decay begins, insects attack them, and woodpeckers come after the insects.” (p. 43).
In light of this misconception, I also think it’s important to reiterate that in the aggregate, the over 36″ size did not show anything near the disproportionately high use of the 25-36″class. In fact, the rate was very slightly higher on the 13-24″ trees.
Regardless of how one interprets this very limited data set, the idea that Ivory-billed Woodpeckers required ‘large trees’ for foraging has become a truism. The reality is considerably more complex.
The next installment will focus primarily on decay class, and the final one will look at prey species. Stay tuned.
As most readers know, I have been very focused on feeding sign, and specifically on bark scaling, for several years and believe I have identified a diagnostic type of work that is beyond the physical capacity of any other woodpecker species. I have been far less focused on excavation because I was convinced that there was no way to distinguish between Pileated and Ivory-billed Woodpecker digging.
In fact, Frank Wiley and I have had a long-running joke about Plate 11 in Tanner and have always wondered why he included it. Based on some feeding sign we’ve found recently, another look at some sign found in May, and a look at online imagery of both Campephilus and Pileated excavations, I suspect that certain types of excavation are suggestive if not diagnostic.
Tanner wrote, “When Ivory-bills dig, they chisel into the sap and heartwood for borers like other woodpeckers, digging slightly conical holes that are usually circular in cross section (Plate 11).”
When I returned from Louisiana in November, I was struck by certain similarities between this excavation:
which I discussed in the most recent trip report, and Plate 11, especially the hole at the upper right and the third hole from the bottom in the plate. I was also impressed by the bill marks at the edges of these holes and by their depth. I then started looking at images from Bill Benish’s Flickr Campephilus group photos and was struck by the similarities, for example:
I then went back to a photograph I took in May of some excavation that struck me as being unusual at the time, although I couldn’t have specifically explained why.
The appearance of some of the holes is strikingly similar to the Pale-billed Woodpecker excavation shown here.
The work in the upper part of the image that’s partially cut off looks more consistent with typical Pileated excavation.
While I’ve not examined digging with nearly the attentiveness that I’ve devoted to scaling, These workings do not look like typical PIWO excavation, examples of which can be found:
Magellanic Woodpeckers, which are more PIWO-like behaviorally and anatomically, appear to excavate in a way that’s more similar in appearance to typical PIWO work, but even Magellanic excavation often seems to have a more jagged and more rounded look than does PIWO.
I wonder if the apparent differences might have to do with preferred food sources – termites and ants for pileateds and beetle larvae for ivorybill. General deep digging is an effective feeding strategy for the former; while more targeted excavation would be more efficient for the latter. Note that the PIWO work in the first image above seems to be targeted (and was likely focused on larvae) but has a much sloppier appearance.
Today, I found another tree with this type of work, not far from the area that we’ve just started to explore and think is very promising. Below are two views of the work. One potentially significant element is that the larger holes appear asymmetrical (Tanner notwithstanding) and more skewed in orientation than typical Pileated Woodpecker foraging trenches, which would be consistent with their being dug with more lateral blows.
While I’m not prepared to suggest that there’s a diagnostic when it comes to this type of feeding sign (and my comments about the excavation from last May are considerably more speculative) , I am starting to think it may be and that there may be a gestalt that is at least suggestive of ivorybill to the experienced and careful observer.
Edited to add: to reiterate, this is an evolving hypothesis, subject to revision or abandonment. I will need to start looking closely at work outside of suspected ivorybill areas and at the work of other Dryocopus woodpeckers.
There may be some value in considering the distribution of the particular type of suspected Ivory-billed Woodpecker foraging sign that I’ve discussed in my recent posts. For the purposes of this analysis, I will limit myself to one very narrow category of bark scaling: extensive work done on the boles of live or recently dead trees (species undetermined in some instances; at least one identified as hickory.) Bark has been tight when examination is possible, and large exit tunnels are abundant. The appearance of the work is consistent – no underlying excavation, no sign of scaling in layers, clean edges.
Two of the trees are in the southwestern section of our search area. This is the general area where I’ve had most of my auditory encounters, although it’s also the area where I’ve spent the most time.
Three of the trees are to the northeast of this pair; two of these were in an inaccessible location and were photographed at a distance of about 40 yards. While they could not be examined for bark tightness, the appearance of the work was consistent with the other examples included in this summary.
Two of the trees are to the east of a parish road (this includes the one discussed in my November update.)
One tree is in the northernmost area we’ve visited and where we’ve spent the least time. Auditory contacts in this area have only involved one source.
The as-the-crow-flies distances involved strike me as being potentially significant. The shortest distance between any two trees is about a quarter mile. The two southwestern area clusters are about half a mile apart at the closest point. From the easternmost tree in these two clusters to the examples east of the parish road, the distance is ~1.35 miles and hence about 2 miles from the westernmost trees. The area to the north is about 2 miles northwest of the easternmost scaling and about 2.8 miles north of the southwesternmost tree.
In 2012, there was a cluster of scaling between approximately .5 miles farther south. The two series of kent-like calls involving two sources heard and recorded in March 2013 came from even farther south.
The distances are much greater than would be expected if a lone pair of Pileateds were engaging in anomalous feeding behavior (there would probably have to be at least three pairs of PIWOs involved.) They’re roughly consistent with the home range Tanner gave for the Singer Tract pairs.
I made a brief visit to our search area from November 14-16. Because I was alone, I mostly avoided the more difficult and remote locations and focused on more accessible areas where possible encounters have taken place. This includes our current camera traps. The weather was a problem – steady moderate rain from 7:00-10:30 am on the 15th and early morning drizzle, moderate winds, and cloudy skies on the 16th, which was also the opening day of duck season. On that day, I ventured farther into the swamp and encountered one duck hunter in an area that appears to get very little human traffic. There was frequent gunfire throughout the morning and into the afternoon; however, even on this day when people were hunting for deer and ducks, I saw only four trucks parked along the parish roads, met two people on the road (one of them having just rescued two hunters who had gotten lost.) This was roughly the same level of traffic as we encountered on the opening day of squirrel season in October. Compared to other places I’ve visited in Louisiana, this is a fairly low level of human pressure, although between the gunfire and the weather, avian activity was suppressed on the 16th. Even the crows were less vocal than usual.
On the morning of the 14th, temperatures were in the mid-20s at sunrise. I visited the camera traps and found what may have been fairly fresh bark chips at the base of one; however, I couldn’t identify any areas of fresh scaling on the tree. Frank Wiley will be servicing the cameras and changing the cards in the near future. Time will tell whether anything was captured this time around. At 9:15, near one of the camera traps, I heard three kent-like calls from the ENE. They sounded very clarinet-like in tone, more so than some of the other calls we’ve recorded. The calls were very close together temporally, and I wrote that the cadence was “not quite what I’d expect.” At 12:55, I was in a different location and heard two more intriguing calls from the SSW (also SSW of where I was at 9:15). A Blue Jay was calling roughly simultaneously from a different direction. I consider both of these incidents ‘weak possibles’ because I was alone and because the calls were so few in number.
On the 15th, I spent most of the morning in the field despite the rain, giving up at 9:30 am. The skies cleared at around 11, and I spent part of the afternoon exploring some habitat to the east of our hot zone. One of our group members has made several visits to this section, but I had only spent one morning there. Because it was unfamiliar territory, I chose to walk the bank of the bayou that bisects it. The understory along the bayou is dense and predominantly comprised of holly, which made for tough walking (and also made it difficult to look for and photograph feeding sign.) I was only able to go about ¼ mile in an hour at which point I turned back. Although I covered very little ground I did find an abundance of feeding sign, including a recently dead snag that had been scaled in the manner that I think is diagnostic, and multiple examples of the scaling on higher branches that is consistent with what Tanner described. The high branch scaling appears to be older, but the work on the snag seemed recent, with fresh bark chips on the ground, so it may be an active feeding site. I’ve included some images to illustrate.
Due in part to weather conditions (which made looking for feeding sign a challenge) and gunfire I did not see or hear anything significant on the 16th, although I went deeper into the swamp following a familiar route. About 2.5 miles in, I came very close to stepping on a large cottonmouth as I stepped over a downed tree. Its mouth was wide open, and it was ready to strike when I spotted it. Just a reminder of how dangerous it can be to wander around alone in the swamp.
I just returned from another visit to the new Project Coyote search area. I have a book coming out in February and will be unavailable during what’s typically considered peak search season. I plan to make 2-3 more trips between now and mid-January. Frank Wiley’s work responsibilities have kept him out of the field since August 1st, except for a very brief visit a few weeks ago. There have been no indications of recent woodpecker work of any kind on the target trees described in the July 6th update. I found another promising and recently scaled feeding tree in the same general area, and we have moved one of our two Reconyx cameras to that location. The trip was a very valuable one for a number of reasons, and assuming that Ivory-billed Woodpeckers are present, we may have some new insights into their behavior.
Weather conditions were extremely difficult from October 2nd through October 5th. Although insects and ticks were nowhere near the issue they were in July, the heat was nearly as intense, and humidity was so high that pre-sunrise hikes into the habitat left binoculars and camera lenses fogged and bodies drenched in sweat. On October 4th, a sudden rainstorm at a time when forecasts predicted a 0% chance damaged or destroyed my camera and ended the field day shortly after noon. Frank Wiley joined me on the 5th, and we were caught in a similar but shorter storm that did nothing to bring down the temperature and added an additional layer of unpleasantness to our late afternoon hike out of the habitat. Conditions were more moderate on the 6th, with the humidity way down and temperatures in the 70s.
It’s also worth mentioning that this weekend was the opening of squirrel season in Louisiana, so there were there were quite a few people in the area, but mostly on the outer edges of the swamp. From Friday-Sunday, gunfire was frequently audible, especially between 7 and 10 am.
I arrived at the location on Wednesday afternoon and spent a couple of hours in one of our hot zones. I did not see or hear anything suggestive. Thursday and Friday were somewhat more interesting, as I discovered some trees that had been fairly recently scaled, including the one on which we’ve now focused a camera (Figs. 1 and 2). While the photographs show work near the base of the tree, there was similar scaling higher up on the bole. The top of this snag had blown down, but death was recent, and the the bark was tight and hard to remove with a hunting knife.
Fig. 1. Recent scaling with insect exit tunnels at the base of a tight bark snag
Fig. 2. Large bark chip beneath fresh scaling
I also found a feeding tree that had both fresh and obviously old and weathered scaling (Fig. 3). This lends further support to the idea that ivorybills return to feeding trees many months apart; we observed something similar on a scaled tree in our old search area in 2010 but did not have a camera on the tree when the second round of scaling took place.
Fig. 3. High branch scaling with signs of at least two visits. Note weathered, older scaled areas and the more recent darker patches at the base and top of the right fork
We suspect the return visits are a response to Cerambycid life cycles, and it appears that scaling takes place both in and out of breeding season. This suggests that maintaining camera traps on suspected feeding trees for extended periods may prove to be a fruitful approach, so we plan to leave our cameras in place for the foreseeable future. We’d welcome input from entomologists about beetle egg laying, pupation, and emergence, as this might eliminate the need for leaving cameras in place for months on end and enable us to deploy them on suspected feeding trees at optimal times.
Over the course of the visit, I noticed a good deal of high branch scaling similar to that described by Tanner and consistent with the appearance of other Campephilus woodpecker feeding sign (Figs. 4-6).
Figs. 4-6. Examples of high branch scaling found October 3-4, 2013
On Thursday and Friday, October 3rd and 4th, I heard isolated ambient double knocks while I was in the vicinity of the feeding tree discussed in my July 6th post. There have been numerous auditory contacts in this area in recent months. Nevertheless, I do not have a high confidence level with regard to these particular sounds, especially because they were isolated and no second observer was present.
On Saturday, October 5th, Frank and I visited the area a few miles to the north where we heard the loud single knock in July. It still remains largely unexplored, but the parts of it we’ve visited are magnificent, top quality habitat, with numerous large trees, abundant standing dead wood, and almost no signs of human activity. At approximately 11:00 am, we heard a single knock that came in apparent response to a series of ADKs. At 1:30 pm, we heard an ambient double knock. In both instances, we agreed about the quality of the sounds (including that they were unlike the gunfire we had been hearing on and off throughout the day) and the direction from which they originated.
Conditions on Sunday, October 6th were a dramatic departure from the preceding days. A front had passed through well before dawn, so the temperature and humidity were moderate. We were into good habitat in the southern search area by sunrise. At 8:28 am, we heard a series of kent-like calls to the northeast of our location. Frank heard two in close succession, the second note lower than the first; I counted six altogether but missed the descending second note. We agreed that they were consistent with other suspected Ivory-billed Woodpecker calls that we have heard and recorded in this area and those we heard and recorded in January 2010 in the old Project Coyote search area. To my ears, these calls are somewhat similar to the ‘kik’ call of the Cooper’s Hawk (with which I am very familiar) but richer and less harsh in tone.
After retrieving one of our Reconyx cameras and moving it to the new suspected feeding tree, we headed north to adjust the placement of our other camera. This is where I heard ambient double knocks to the northeast on Thursday and Friday. At approximately 1:45 pm, we both heard two double knocks to our southwest. These appeared to come in response to and within five minutes of a series of ADKs that Frank had performed. Frank heard a third double knock two to three minutes after the first two, but I missed it. Two to three minutes after Frank heard the double knock, we both heard a single knock, apparently from the same location. We waited an additional ten to fifteen minutes and heard nothing further, leaving the location at a few minutes after 2 pm and walking in a southwesterly direction.
At 2:15 pm, I heard several kent-like calls, identical in quality to the ones heard earlier in the day. I stopped and asked Frank, “Did you hear that?” He indicated that he had not, but another call followed, and it was readily audible to both of us. We agreed that the calls seemed to have come from the same general area as the double knocks we had heard approximately a half-hour before.
As we discussed what had been an extraordinary day, even for this area where the possible contact rate has been extraordinarily high, Frank noted that no kent-like calls had been heard since early March, when another searcher and I heard and recorded suggestive calls in the morning and afternoon, this despite frequent visits to the area by several searchers, including Frank’s almost daily presence from late June until August 1st. Frank has been in the field at all seasons, and I visited the former search area into June in 2010. We are not aware of having heard any suggestive calls before October 1st or after mid-April and certainly not any series of calls. We are aware of kent-like sounds being recorded during summer in other parts of Louisiana but suspect that calls are rare during the late spring and summer months and that the dramatic change in weather conditions and the first cool day of the year may have triggered the vocalizations.
To be continued. .
Edited to add: I have re-examined the high branch scaling in Figure 6., and on a closer look, there are indications that the bark has been scaled in layers. I will leave the image up, but I think it may well be Pileated Woodpecker work; it is certainly not what I would classify as Grade A. The other posted examples do not share this layered appearance. While I always look for ‘Tanneresque’ scaling, it has been my view for some time that (Tanner notwithstanding) the most suggestive and perhaps diagnostic work can be found on boles rather than on high branches.