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In Which Someone Proposes Red-breasted Nuthatch for the March Calls

Someone recently proposed Red-breasted Nuthatch as the source of the March calls and pointed me to this clip.

It’s worth listening to the recording in tandem with some of our putative ivorybill calls. The pitches do sound close.

The habitat isn’t really right for Red-breasted Nuthatch. I’ve never encountered any in the search area, even during irruptions, and the area from which the calls were coming has no conifers. The two calls I heard did not sound like nuthatches to me, and Matt Courtman, who knows the species well, categorically rules out nuthatch of any kind. Nevertheless, I took the opportunity to revisit the sonograms and listen to a whole lot of nuthatch calls.

There’s definitely a similarity, but I’d describe the Red-breasted Nuthatch calls as being buzzier in quality. The harmonics are dramatically different, which accounts for the difference in sound.

For those unfamiliar with sonograms, the X axis is time (in seconds) and the Y axis is frequency.

Red-breasted Nuthatch toots consistently have a fundamental frequency of around 1000 hz; most of our recorded calls have a fundamental that’s closer to 500-600. The strongest emphasis in our calls is on the third partial, usually between 1600-1900 hz. Most of the emphasis in the RBNU calls is on the fourth and fifth partials, in the 2500-3500 hz range; these partials, when visible, are much weaker in our putative ivorybill recordings.

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Typical Red-breasted Nuthatch sonogram. Note the weak fundamental at over 1000 hz and the strong 4th and 5th partials.

 

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Putative Ivory-billed Woodpecker recording, March 15, 2017. Three calls are visible to the left of the white vertical line. Note the stronger fundamental frequency at around 500-600 hz, the weaker second partial, the strong third, and faint, weaker higher partials.

Finally, for reference, it’s worth checking out the White-breasted Nuthatch, both the call and the sonogram. As discussed in a previous post, White-breasted Nuthatches are present in the area, and a number of their faint calls are captured on the recording.

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White-breasted Nuthatch sonogram, showing a weak first partial at approximately 1000hz, strong second and third partials, and somewhat weaker fourths.

In an earlier post, I mentioned that Tanner suggested that ivorybill calls were more like Red-breasted Nuthatches, while Hasbrouck described them as being “exactly like the note of the White-breasted Nuthatch”. I’m still on a learning curve when it comes to bioacoustics, but the harmonic structure of White-breasted call seems closer to known ivorybill calls than is the call of the Red-breasted.

The difference in tonal quality that was apparent to my ears is explained very succinctly on the Earbirding blog:

All nasal sounds are stacks of partials, but not all stacks of partials sound nasal. The tone quality of a complex sound depends on which partials are loudest—that is, darkest on the spectrogram.

The higher the darkest line in a stack, the more nasal the sound.

Known ivorybill calls have a strong 3rd partial and are on the less nasal side of the nasal spectrum; the strength of the 3rd partial became more apparent when the Singer Tract calls were played back and recorded at a distance of 145 meters. Red-breasted Nuthatch calls with their strong 4th and 5th partials are considerably more nasal. The White-breasted falls in between, with strong 3rd and 4th partials.

Tanner wrote that the calls of the ivorybill are “much longer and pitched higher than the White-breasted Nuthatch” and “are more in the range of the Red-breasted Nuthatch”. To reiterate a point made previously, this suggests that typical “kents” were of considerably longer duration than the calls on the Singer Tract recordings, as is the case with the calls Phil and Matt recorded in March. This is important to note, since Cornell, following the Singer Tract recordings, has assumed a duration of 60-100 milliseconds for ivorybill kents, whereas kent-like Red-breasted Nuthatch calls are much longer, often upwards of 300 ms, and White-breasteds seem to be in the 100-200 ms range. One outside reviewer provided durations for eight of the calls we recorded, and they vary considerably, from ~80 ms to ~350 ms.

Whatever these mystery sounds may have been, I’m sure they’re not Red-breasted Nuthatch. They’re not White-breasted Nuthatch either. Nor are they a good match for Blue Jay or Turkey. Carefully considered, serious suggestions are welcome.

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Trip Report: June 7-11, 2017

This most recent trip was very snakey, meaning I nearly stepped on several – cottonmouths and timber rattlesnakes. In all my years of searching, I’ve seen six rattlers, three on the most recent trip.

Rather than do a day by day log, I’m just going to post the highlights this time. I took few photos, mostly of reptiles.


I made this trip with absolutely no expectations, given the time of year, although I had hopes that one of our target trees might have been hit. As is so often the case, my hopes went unfulfilled, even as my expectations were exceeded.

I was joined by wildlife biologists Tommy Michot and Peggy Shrum for the entire trip. Phil Vanbergen came along on Saturday. Phil has heard Pale-billed Woodpecker double knocks, and Peggy has heard numerous Campephilus DKs while doing fieldwork in South America.

There was no fresh work on the hickories we have targeted, but we are reviewing the trail cam photos nonetheless. We found another hickory that recently lost its top and have targeted it, along with a nearby hickory and a beech, with our remaining trail cam. The cavities discussed in an earlier post are currently obscured by foliage.

We had possible auditory encounters, all knocks, on Thursday, Friday, and Saturday, and while I would label most of what we heard as “weak possibles”, the Thursday knocks were within one of our “hot zones”, not far from where the March recordings were made. The Friday knocks were in a different area, one we visit infrequently. In most instances, these knocks were heard by one or the other of us, but on Friday, we had some instances where two or all three of us heard them. And all of the Friday knocks were heard in the same general area over a couple of hours.

The Saturday knocks were a lot more interesting. Here’s a detailed description:

Tommy, Peggy, Phil, and went to deploy the trail camera. Peggy has heard many Campephilus DKs in South America, and Phil has heard them in Costa Rica. We heard a possible ambient knock (I can’t be sure if it was an SK or DK) while walking; it was quite loud, but we initially dismissed it as a gunshot. About an hour later, after deploying a trail cam, we set up and did a series of Barred Owl playbacks followed by a DK series. I turned off the recorder after about 15 minutes, but we remained in the area, talking quietly. At 28 minutes after the DK series, we heard a loud SK followed by an apparent DK 5-10 seconds later. We considered and ruled out gunshots (absolutely impossible given the context) and tree fall (light winds, no rain since Tuesday, no rustling of leaves or other accompanying sounds, length of the interval between the first single knock and the subsequent double). Both Phil and Peggy thought it was very good for Campephilus. The source of the knocks was close, probably no more than 200-300 yards away.

About three minutes later, Phil and I heard another more distant DK; we both thought it was quite good, but Peggy and Tommy missed it. My recorder was running at this time, but it did not capture the sound.

After discussing it, none of us felt a gunshot was likely for the earlier knock, since there was no other shooting all day; it seemed to have been fairly close; in June, the only hunting in the area is for hogs, and it is infrequent; the road is quite a distance away; and we hadn’t seen another vehicle in the area all week.

I’m looking forward to returning in October and hope to have enough material for a couple of posts before then. I’m also delighted to have Peggy on board as part of the team; she brings a lot to the table. I’m hoping that coming seasons will involve an expanded team and a more concerted effort, so that we can obtain something conclusive or rule out ivorybill. My only regret about this most recent trip is that I didn’t harvest more chanterelles and didn’t start collecting them until our last day in the field. They were everywhere, and they are delicious.


Project Coyote’s Future and Two Trip Reports from March

The audio obtained in March took precedence over the trip reports and a few other things I’ve been meaning to address for some time. They’re worth a listen if you haven’t done so already.

Longtime readers of the blog have probably noticed the donate button and the advertising that now appears on the site. Project Coyote has been mostly self-funded from the start, except for a few donations from anonymous individuals and the Rapides Wildlife Association. Some used equipment has been passed on to us by other groups of searchers. I’ve long believed that we’d be able to document ivorybill presence (or go a long way toward ruling it out) with more consistent coverage in the area and a relatively modest budget.

At this point, remote recording units and a couple of additional cameras are at the top of the wish list. Ultimately, I’d love to be able to cover costs for our core group and to provide funding for one or two people to be in the area steadily, at least during February, March, and April. I can dream . . . Anyway, your contributions can help make some of this possible.

Before Frank’s passing, I had decided to ‘retire’ from active searching after this season, for a number of reasons – the sense that I had nothing further to say about feeding sign and the fact that I did not personally see or hear anything strongly suggestive of ivorybill presence in the 2015-2016 season among them. The lack of recent work on hickories was particularly discouraging.

Things started to change when Frank was in the hospital. It became clear that our search was important not only to Frank but also to his family and friends. A number of long-time, mostly quiet, enthusiasts and supporters (including Matt Courtman who had visited the area with Frank some years ago) reached out and encouraged me to continue and even to intensify the effort.

Shortly thereafter, Phil Vanbergen found some recent scaling of the kind that I think is diagnostic for ivorybill on two hickories, though it turned out the work was not as fresh as initially suspected. The trail cam capture of a PIWO removing a strip of bark from one of the trees led me to begin my first March trip in a somewhat pessimistic frame of mind. It didn’t take long for that to change – another ride on what I’ve taken to calling the IBWO-llercoaster.

I arrived in the search area on March 9 and met up with two out-of-state birders with whom Frank and I had been corresponding for some time. I showed them around the search area. They were impressed by the habitat, but we did not see or hear anything significant. On the morning of the 10th, I sent an email to some of the team expressing my frustration over not having had a “compelling recent encounter” and stating that my possible October sighting didn’t meet that standard (even now, I don’t think it compares to the March recordings.)

I was on my own on the 10th and had a slightly less discouraging day; I got my first opportunity to examine the scaled hickories Phil had found. This strengthened my suspicion that the recent PIWO work was “wake feeding”.  Later, I met Matt for dinner and a strategy session.

Everything changed on the 11th. In addition to satisfying myself that the extensive scaling on the hickories was at least several months old and that the recent Pileated activity was likely secondary scaling (based primarily on the small bark chips); over the course of the day, we deployed three of our four trail cameras.

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Even more importantly, we had auditory encounters in both the morning and the afternoon. Here is my write up from that day, with a few redactions.

At about 10:15, we were in close proximity to where we’ve had several possible contacts, most recently when I was out with Frank in October. We’d just deployed a second trail cam, and Matt had gone about 50 yards north and west of Phil and me. He texted and asked if he could do some DKs (he’s using two wooden blocks that he knocks together.) He did several, no particular pattern, mixed ASKs in with the ADKs.

I did not take notes, and my memory of the exact sequence is weak, but I heard 5-6 DKs and SKs coming from the east in response. If I remember correctly, there was at least some interplay between the ADKs and the DKs, meaning that there were a couple, and then a pause, then Matt DK’ed and there were replies. Matt said he heard 4-5, and I think Phil said he heard 3-4.

Whether or not I’m misremembering, it was far and away the most compelling series of responses I’ve ever heard, and I’ve done hundreds of ADK sessions. **** this was similar to what you encountered on your first trip, in the same general vicinity, but a lot more dramatic. In addition, there was no ambient foraging, and other than the responses, all we got was one PIWO drum from a different direction. Phil said that one of the DKs was very similar to the Pale-billed DKs he heard in Costa Rica last summer. 

For the kents, we were at a different location a few miles away; the time was approximately 2:45 pm. Phil and Matt heard a number of calls, of which I only heard two. Of the two I heard, the first was on the low-pitched side, I’d say close to the pitch of the what Tanner called “conversational” calls on the Singer Tract recordings or what Frank and I called the “wonka wonkas”; it had a trumpet-like quality, maybe more than I’d expect for an IBWO, but still in the ballpark. The second was higher pitched and more tooty/reedy, very close to the Singer Tract recordings. The wind was dead calm for the second call, so it was not a tree squeak. In both cases, the calls came from the East.

. . . 

So there we are. Quite a day. Now, if we could only find out what’s making the sounds and what’s knocking the bark off the hickories at the outset.

For those who missed it, here’s Phil’s recording of two of those calls – headphones or good speakers recommended. We did not record the knocks we heard in the morning.

On the 12th, Steve Pagans, Matt, and I returned to the location and heard 1 ambient DK and 2 SKs, at approximately 1:55 pm.

These sounds came from roughly the same direction as the calls we’d heard the day before. The possible DK was not as loud as the SKs, or as yesterday’s knocks, but it was distinct. Matt did some ADKs. There was a Red-bellied Woodpecker foraging to the south of the direction of the knocks. Matt’s ADKs seemed to induce it to bang more frequently and forcefully, but we didn’t hear any distinctly IBWO sounding knocks in response. Steve and I heard a single possible kent from the same direction as the possible SKs and DK. It was faint. Steve heard it better than I did and thought it was good; Matt didn’t hear it all. This was probably due to how we were positioned in terms of proximity to the sound.

Under normal circumstances I’d label this episode as a fairly weak possible, marginally worthy of mention on the blog. But given the location, it seems more significant.

The 13th was also eventful. Matt and I opted to return to the area where we’d heard the knocks on the morning of the 11th and give the other location a rest. Here’s my write up of the morning’s possible auditory encounter.

We decided to do a mix of playback and DKs at 9:40 AM. I did about a minute and a half of playback, using the iBird app (3 rounds – 28 seconds of Kents, “conversational” calls, and tapping). Matt followed with perhaps a minute of knocking wood blocks together. Over the course of the following five minutes, we had several knocks. Initially, Matt heard a single that I think I missed. It was followed by a very loud knock coming from the East. It was VERY loud and clear, what Frank would have described as some banging on a tree with a baseball bat. Shortly thereafter, another sound came from my left, roughly north of us. Matt heard it as a single, but I heard it as a double, with the second to my ears perhaps the closest thing to what Tanner described as an echo of the first I’ve ever heard. After that, we heard another loud single roughly from the southwest. The last was more distant and somewhat less striking.

The first single knock and the one I heard as a double were astonishing. There’s no doubt in my mind or his that these were neither mechanical sounds nor foraging. I am kicking myself hard for not having my recorder running; I’ve gotten too jaded about auditory encounters, and it’s a little tough to manage both recording and generating sounds.

A little later, I found a dying chestnut oak with some mildly intriguing feeding sign. There were some huge, thick bark chips on the ground and this, more than the appearance of the work on the tree, struck me as potentially suggestive; this is the first interesting work I’ve found on an oak in several years.

Matt and I returned to this location on the morning of the 14th. Matt did ADK series on the half hour until shortly before noon. It was a cold and windy morning, uncomfortably so. We heard nothing of interest.

On the 15th, I headed for New Orleans and my flight the following morning. Phil and Matt returned to the woods and captured numerous calls between 7 and 11 am. When I heard the recordings I cleared the decks and made arrangements to return as soon as I possibly could.

Patricia and I were back in the woods by lunchtime on the 23rd. Louis Shackleton – a good friend, professional photographer, and birder who happened to be in Louisiana – joined us on the 24th. We didn’t see or hear anything of interest and left early ahead of predicted heavy rains.

At shortly after 11:00 am on the 25th, Patricia and I heard some possible double knocks in apparent response to some very aggressive knocking on my part; two of these knocks came from roughly north and one from the east (the same direction from which the March 15th calls were coming).  I’m still reviewing the audio from this trip and may have additional material to post in the future.

I went out alone on the 26th, returning to the same vicinity, and did not see or hear anything interesting.

We were rained out on the 27th. On the 28th, I found a large cavity not far from where the calls were recorded. It does not appear to be fresh enough to be a recent nest, but we plan to target it with a trail cam in the event that it’s being used as a roost. This find illustrates how difficult it is to spot cavities in our search area – six people had spent the better part of multiple days in the immediate vicinity before I noticed it, and the snag is in plain view.

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More storms came through on the night of the 28th, and the next morning Patricia and I decided to take a break from the “hot zone” and instead visited the area where Phil found the recently scaled hickories and where Matt, Phil, and I had heard knocks on the 11th and 13th. We found that one of Phil’s scaled hickories had lost its top, which gave me a chance to examine one of the scaled areas up close. As expected, the wood was somewhat punky, and and the bark was fairly easy to remove by hand.

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We also discovered that the top of one of our target hickories had been blown off. The tree shows signs of beetle infestation, which gives us reason to hope that it will be visited by woodpeckers before too long.

It was interesting to get a close look at this freshly fallen top and examine how hickory bark separates from the trunk under these circumstances. While it seems to come free fairly easily in very large strips, the bark is extraordinarily tough and strong. When fresh, it’s flexible but very hard to break; doing so requires twisting, and it won’t fracture. Within about 48 hours the piece I collected had dried out and become surprisingly hard. This further reinforced my view that Pileated Woodpeckers are not anatomically equipped to scale large chunks of bark from live or freshly dead hickories.

It was a beautiful day in the woods, and some of the other highlights included recently hatched Wood Ducklings, a posing Yellow-crowned Night Heron, and the first ‘gator (a small one) I’ve ever seen in the area.

The next morning, I returned and redeployed a second camera, which had been trained on another nearby hickory, to the one with the downed top so that we can cover the entire stub.

We spent the morning of the 31st in the area where the calls were recorded before catching an afternoon flight. We did not note any interesting sounds while in the field, but after listening through Patricia’s recordings, I noted the possible double knock discussed in the previous post.

I’m planning two more trips before summer. I anticipate that we’ll have all cams deployed and have high hopes for the hickory stub.

Meanwhile, I thought I’d throw in some additional images that may help to convey what a special and magnificent place this is.

 

 

 


Possible Double Knock in Reaction to a Barred Owl

For a slight change of pace, I’m posting this possible double knock in reaction to a calling Barred Owl that Patricia Johnson captured at 8:40 AM on March 29th, within 50 yards of where the calls were recorded on March 11 and 15. I’m posting this particular double knock because the context may give it added significance – the apparent reaction to the Barred Owl call and the fact that there was no temporally proximate ambient foraging.

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I’m somewhat hesitant about posting recordings of knocks, especially those not noted in the field, for a number of reasons: our field tests have revealed that in deep woods, ADKs can sound like single knocks at a couple of hundred yards; it’s also not uncommon for observers to disagree about whether knocks heard in the field are singles or doubles, and the same is sometimes true about recordings. In addition, most of the interesting knocks captured last month are faint on the sonograms, and in the case of the knock posted below, the second knock does not show.

Nevertheless, this double knock appears to be in the right range for Campephilus in terms of the interval and the pattern – louder first knock followed by a softer second one.

Edited to add: Another reviewer has suggested that the knocks are “too slow”.

I’m two trip reports behind and hope to get to them before returning to Louisiana.


More Recordings from March 15: Approximately Three Hours of Kent-like Calls and Analysis

On March 15, Phil Vanbergen and Matt Courtman recorded numerous kent-like calls at the same location where we heard several calls on March 11 and 12. Phil was able to record two of the March 11 calls. That capture is included in the post, along with Phil’s audio from the morning of the 15th. I heard two of the calls on the 11th; the second one in particular struck me as being consistent with the Singer Tract recordings; the first seemed a little low pitched to my ears, an observation that’s captured on the recording. Steve Pagans and I heard several calls on the 12th, but these were not recorded.

Matt obtained nearly three hours of audio, and to my ears the sounds are coming from 2-4 distinct sources; I had the same impression after listening to some of Phil’s clips. I have now listened all the way through Matt’s recordings several times and will share my analysis below. Matt and Phil are likely to weigh in later with their perspectives. I also have a couple of trip reports pending, so there should be a lot of activity on the blog in coming weeks.

To start with, I counted over 200 kent-like calls in all.

On the long clips posted here, I’ve edited out all of Matt’s ADK (anthropogenic double knock) series, which he did on the half hour. The knocks are very loud, as can be heard from the one trailing sound I’ve left in. I also snipped out several minutes of conversation between Phil and Matt. The ADKs seem to have led to more frequent calling and may have provoked some double knocks, something we may address in a future post.

Edited to add: On further review, there does not appear be a correlation between ADKs and more frequent calling. Clips like the one posted below can be deceptive. One kent-like call that overlaps with a knock has been deleted. There is also one possible knock in response. Caution, ADKs have not been completely spliced out, and they are loud. See bottom of page for brief clip and sonogram.*

Between 6:12 and 6:25 on the last long recording made that morning, there are five calls of differing durations and volumes, followed by what may be a double knock. Similarly, at the end of the full clip, starting at 14:14, 3 calls are bracketed by some potentially interesting knocks, 2 before and 1 or 2 after.

The first four clips below are shorter, amplified extracts on which the calls can be heard easily.

The first two of these are extracted from the final segment described above and include the interesting, tooting sounds and possible knocks.

The third clip includes multiple calls over 2 minutes and nine seconds, along with a wide variety of other sounds.

The fourth is four minutes long (pardon the airplane noise) and should provide additional context while also revealing some of the variations among the calls.

For those, like me, who don’t have professional sonogram software, I recommend using Sonic Visualizer – an easy to use, free program that enables you to watch the sonogram as you listen.

And for those who are unfamiliar with avian bioacoustics, this is a great place to start. I’m on a very steep learning curve myself and am prepared to stand corrected about any misstatements in this post.

Many of the sounds are audible on built-in computer speakers, but playback through headphones, earbuds, or external speakers is highly recommended.

 

I think these calls were likely made by Ivory-billed Woodpeckers. My perspective is based in part on the fact that I have spent all or part of nearly 40 days in close proximity to where the calls were recorded, starting in 2014. A considerable amount of this time was spent sitting quietly, and the total person hours spent in the area is well into the hundreds. We have had occasional kent-like calls, possible double knocks, and possible sightings over the years, but nothing approaching what transpired on the 15th.

Matt spent the morning of the 16th in the same location and did not hear any of the sounds, and Patricia and I spent 4 mornings and one afternoon there between the 23rd and 31st and heard no similar calls. I think this militates strongly against the idea that the source of the sounds is a common resident of the area.

Three alternative hypotheses have been suggested.

On the morning of the 15th, Phil proposed that the sounds might be tree squeaks. There appear to be multiple tree squeaks on the recording, some with similar pitches, but they bear little resemblance to the kent-like calls on the sonogram or to the ear. In addition, the calls sometimes come singly, sometimes in groups, and they vary in pitch, volume, and duration and seem to occur independent of wind velocity (on the 11th we noted that there was no wind.)

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Sonogram of first clip, showing apparent tree squeaks before and and immediately after two kent-like calls – the stacked horizontal lines right of center.

The first sound, at just after 4 seconds on the second clip, seems ambiguous. The sonogram is somewhat similar to the kent-like sounds, but the duration is very short, and it has a creaky quality. It’s also associated with the two creaky sounds that follow. These can be heard frequently over the course of the morning, and their appearance on the sonogram is nearly uniform.

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Sonogram of second clip showing tree squeaks.

One reviewer proposed Wild Turkey and Blue Jay as possible sources. I think turkey can be ruled out due to the absence of other turkey-like sounds associated with these very persistent calls.

Blue Jay strikes me as a more plausible alternative. Blue Jays can be heard at numerous times on Matt’s recordings. And Blue Jays are known to make kent-like calls, some of them very similar to known Ivory-billed Woodpecker sounds. This is likely not mimicry, since the most similar recorded calls I know of were obtained in upstate New York. The recordist noted the similarity. On the sonogram, the resemblance between these calls and either known Ivory-billed Woodpecker sounds or Matt’s recording is not as strong as it might seem to the ear. While they share a strong third partial, the Blue Jay fundamental is higher and some of the higher partials are considerably stronger.

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Kent-like, suspected Ivory-billed Woodpecker calls recorded by Matt Courtman on March 15, 2017. Note the relatively strong base frequency and 3rd partial, and weak 2nd, 4th, 5th, and 6ths.

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Kent-like Blue Jay calls. Note the relatively weak fundamental and strong second through fifth partials.

It’s also important to note that on the Cornell Blue Jay recording, the kent-like calls are intermixed with typical Blue Jay vocalizations. Over the three hours of Matt’s recording, kent-like calls occur during periods when Blue Jays are vocalizing and during periods when Blue Jays are silent.

Some of the kent-like calls have harmonics consistent with Cornell’s recorded playbacks of Singer Tract calls at 145 meters. Many are lower in pitch. Most have a considerably longer duration, although to my untrained eye/ear, some seem close to the 80-100 ms duration on the Cornell recording. More on duration below.

On March 28, I did some playback of Singer Tract calls using an iPhone and a bluetooth speaker. Patricia recorded them on a Roland Edirol R09HR digital recorder. I’m including the recording and the sonogram for comparison. Like Matt’s recordings, the second partial is strong throughout, and the 1st, 3rd, and 4th appear to be weaker than for the Blue Jay shown above.

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At various points, Phil also experimented with doing playback, using calls recorded in 2010 at the old Project Coyote site. (He also played back several other species – Red-bellied, Golden-fronted, and, possibly, Gila Woodpecker to gauge Red-bellied response, and Eastern Towhee out of personal interest.) Examples of putative ivorybill playbacks can be heard over the first 3 minutes of the fourth long clip posted above and also during the first part of the fifth. These sounds are longer but similar in tonal quality to the lower pitched calls. Their harmonic structure is different, however, with a fundamental at around 800 hz, a second partial at around 1600, and a fairly strong higher partial at approximately 5000 hz., and should be readily identifiable on the sonogram.

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Higher pitched playback calls, at middle left and far right.

Phil’s playbacks do not seem to have provoked any kent-like replies. Blue Jays can be heard during the same time frame, but it’s not immediately apparent whether the recorded Blue Jay calls are responses or merely contemporaneous vocalizations. This segment includes some Blue Jay vocalizations.

With regard to Blue Jays and the numerous kent like calls heard from March 11, 12, and 15: to reiterate, many hours have been spent in this vicinity, with close attention being paid to kent-like sounds. These are heard infrequently and never before in such quantity or over such an extended period. If Blue Jays in the area were making these sounds, we almost certainly would have heard and recorded many of them over the years. In addition, both Steve Pagans and Matt Courtman are experienced and skilled ear birders and neither thinks these are Blue Jay calls.

It’s also worth pointing out that another potential confusion call can be heard on the recordings – White-breasted Nuthatch. The sound is similar but much weaker, as should be clear from the amplified March 15 excerpt. On the sonogram, just below the amplified recording, the calls show up very faintly, with dominant frequencies of around 2200-2400 hz and a relatively strong partial at 1700-1800.

 

 

I encourage people to listen through and draw their own conclusions. Input from those with expertise is welcome.

While I can’t say if any of these calls are a perfect match for the Allen and Kellogg recordings (some may be), many of them are close on the sonogram and similar to the ear. It’s important to bear in mind that the Singer Tract birds were likely agitated when those recordings were made, even though Tanner described some them as being good examples of kents. It’s also important to read Tanner’s descriptions carefully, though as is so often the case, his writing can be opaque. Perhaps his most important observation was that “all of the notes have the same nasal, trumpet-like quality.”

According to Tanner, “The notes of the nuthatches are the only bird calls I know that sound like the voice of an ivorybill; the Ivory-bill’s calls are much longer and pitched higher than the calls of a White-breasted Nuthatch, are more in the range of a Red-breasted Nuthatch.” (Emphasis added.) By contrast, Hasbrouck, writing in the 1890’s, described it as being “exactly like the note of the White-breasted Nuthatch” only much louder and stronger.

Tanner’s reference to Red-breasted Nuthatches has always confused me. I’m very much in Hasbrouck’s camp; I think the Singer Tract kents sound far more akin to White-breasted than Red-breasted Nuthatch. Either way, most of the Allen and Kellogg kents are lower pitched than typical White-breasted Nuthatch calls, as are the ones on Matt’s recording. In addition, the Allen and Kellogg kents seem to be of similar in duration to typical nuthatch calls, rather than longer or “much longer”. This too suggests that they are not typical but are more rapid and perhaps higher pitched due to agitation. Tanner wrote further, “[t]he kent note, given in monotone or infrequently, is the ordinary call note. When the bird is disturbed, the pitch of the kent rises, and it is repeated more rapidly, frequently doubled, kent-kent, with the second note lower. The prolonged and slurring, kient-kient-kient call I always heard when two or more birds were together.” This call was never recorded.

According to Allen and Kellogg, “kenting varied a great deal” and a male bird called “loudly and deliberately”, again suggesting that many calls were of longer duration than those on the recording. Tanner’s notes also point to this variability. At one point, he wrote of “1 and 2 syllable yaps”; he has the Mack’s Bayou bird (whose voice he claimed he could recognize) making a “kient-kient” and also transliterated calls with “keent keent” and “yeenh yeenh” (Bales). These renderings all suggest a more drawn out call than those on the Allen and Kellogg recordings. George Miksch Sutton described the Singer Tract birds’ calls as, “strange, bleat like, not quite sharp enough for a woodpecker’s cry. It was slightly nasal in quality and it sounded to me like ‘Gip!’, with a hard g“. Sutton’s description also suggests that many kents had a fairly long duration.

Edited to add: similarly, several observers (Audubon, Beyer, Hoyt)  described ivorybill calls as “plaintive”; this too seems to imply calls of longer duration than what’s heard on the Singer Tract recordings.

Given the resemblance to the Singer Tract recordings and the lack of plausible alternatives, I posit that these calls are at worst highly suggestive of Ivory-billed Woodpecker.

*Possible knock and kent-like calls temporally associated with ADK series. Caution remnant ADKs are loud.

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Trip Report December 16-21, 2016, Part 2

Part 1 of this report is here.

Patricia opted to take the day off on the 19th, so I went out on my own and covered a lot of territory. I had been thinking hard about the hickories and the fact that, in virtually all cases, we’ve seen indications that bark is removed from these trees and stubs within a very brief period or perhaps in a single visit and that other woodpeckers don’t seem to begin working heavily on these trees for extended periods, sometimes for years. Except for changes in color due to exposure to the elements, some of the scaled surfaces we associate with Ivory-billed Woodpeckers can retain their distinctive appearance for at least three years and more likely five or more.

Steve Pagans later explained that this is due in large part to hardening by compression; hickory wood is hard and dense to begin with, and when a tree or stub is leaning, the wood that’s absorbing more weight becomes even denser, harder, and more impervious to rot. Thus, on many of these trees, Pileated Woodpeckers will have worked on the rotting side, sometimes extensively, while the compressed side remains very hard and virtually untouched by woodpeckers.

I examined and marked as many of these trees as I could over the remainder of the trip. Unfortunately, we did not find any of this scaling in the 2015-2016 season. Trying to find more of it this year and trying to find a way to identify potential target trees before they’re scaled will be priorities for me.

I plan to write about this work on hickories and what I think it suggests in an upcoming post. For now, suffice it to say that these particular snags and stubs are a kind of twofer having the decayed substrate that’s preferred by Pileateds and and the hard wood that, following Tanner, is preferred or used exclusively by ivorybills. As noted elsewhere, some bark on these snags and stubs can remain tight for years, and on one of the trees I examined, it was still difficult to remove, even when it had reached a point at which some of it would crumble to powder when it was being pulled off. More importantly, the harder surfaces show modest expansion of exit tunnels and targeted digging work that appear to be associated with the initial scaling (as in the hickory on the homepage and the one in Steve’s photo at the end of this post, both of which were very freshly scaled and alive when found) and little or no other work for a period of years, even when there are signs of infestation by multiple insect species (based on the presence of exit tunnels that vary greatly in size and shape). I’ve included multiple examples, long shots and details, to illustrate.

On the 20th, Patricia, Steve, Phil, and I went to Sector 2 together. We went through the area where I recorded calls in 2013 and where we found concentrations of scaling in spring 2012 and during the 2012-13 season. There has been none since in this little patch. We found no recent looking bark scaling in the morning (as it turned out, we missed a group of three sweet gums with high branch work perhaps a quarter mile to the northeast of this area, see below.) One odd highlight was coming across a patch of forest floor with many of these beautiful ice formations that had formed around the stems of a couple of species of plant.

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At a little before noon, Steve opted to turn back; we had already covered 2.3 miles. Before we went our separate ways, we all speculated on and were baffled as to what might have damaged this sweet gum. The wounds seem to have been caused by a scrape, but there were no downed trees or tops anywhere in the immediate vicinity.

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Phil, Patricia, and I proceeded another half mile farther north, reaching a hickory stub that I found in the spring of 2013, shown below. The stub was still standing, and the areas with putative ivorybill work had lost more bark but showed no signs of further woodpecker activity. The presence of a click beetle in this 2013 photo suggests that parts of the tree were already starting to rot even then.

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We found two sweet gums with extensive scaling on large branches within 30 yards of this snag. Some of the work was recent. This is something that we’re finding repeatedly; even within clusters, the interesting feeding sign often seems to appear in tighter groupings involving two or more trees. I’ll provide a possible explanation in my next post.

We found a particularly unusual bark chip at the base of the tree on the left. While it comes from a relatively small branch, the way it was removed may be significant. Over 1/3 of the chip is cylindrical encompassing almost the entire circumference of the limb; it was not pecked off piece by piece; instead, it appears to have been loosened by several blows and then pried free. The bark is hard, suggesting it was tightly attached; it was moist and contained a good deal of frass when found. The piece is very large, approximately 13″ long and nearly 7″ in circumference.

On the return trip, we found a small group of three sweet gum snags, somewhat on the longer dead side. All three had recent to fresh scaling, and there were very large bark slabs at the bases of two of them. These slabs of bark were dense and hard, suggesting that they were tightly adhering when stripped.

We came across a massive relict cypress on the way back. It’s not the first time I’ve seen this tree, but it never fails to take my breath away.

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~7′ DBH cypress. Dec. 2016. Photo by Phil Vanbergen

On the morning of December 21st, Phil and I went to Sector 1, and Patricia and Steve went to Sector 3. We decided not to deploy a camera on the downed top we had found on the 16th. We have two functioning cameras at the moment, and it seemed more prudent to deploy them on untouched substrates. We didn’t find any new scaling or a substitute target, so we decided to head for Sector 3 where I had a couple of targets in mind.

As we were walking to the car, I got a text from Patricia saying that she and Steve had just had a possible auditory encounter. Steve is a dedicated birder with very good hearing and excellent ear-birding skills. Patricia has limited experience, but she is a retired opera singer with a good general ear. Here are their descriptions of the morning’s events.

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Steve: At about 9:10 am, Patricia and I were in the bottomland hardwood area in Sector 3. The weather was overcast and cold without any wind – very good conditions to hear bird calls. We had walked southward for about a quarter of a mile in the bottomland area when we had decided to do some DKs. Actually it was Patricia’s idea to do some DKs, and we proceeded to find a small American Holly that was the right size to cut two sticks for knocking.

Patricia: I thought it would be a good location, as I remembered Frank, Steve, Mark and I had done them at the same location a few years back. I remember the fallen tree we all sat on for lunch. Steve had sardines! And where Frank sat down at the base of a tree and started to snore. When I mentioned to Mark that Frank was sleeping, Frank retorted “I’m not asleep”

Steve: The location is one where we could see for a distance fairly well. When we started the DKs, we did not keep up with how many were done or how long we did them, but I think it was for about 10 minutes. We made an effort to keep watch for an incoming IBWO that would be responding to the DKs, but we were probably not as diligent as we could have been. At a point we had engaged in some conversation. I was sitting on a sweetgum log and Patricia standing about six feet away. My right side was facing south. Patricia was talking when all of a sudden I heard what sounded like at least two distinct calls from my right. The calls sounded like textbook calls of the IBWO – a bit like a toy horn was being blown. I know White-breasted and Red-breasted Nuthatch calls very well and what I heard did not sound like either of those birds. I immediately put up my left hand to stop Patricia from talking and pointed with my right hand toward the south. I told her what I had heard while we both strained to hear any more calls. There were no more calls. Also, we did not see the bird. It is highly likely that we did not spend enough time watching and listening for the bird after I had heard it call. It is hard to say how close the bird might have been to our location because I don’t know how far their call can be heard.

Patricia: I think I did about 10 DKs, perhaps 15-30 seconds apart. When I didn’t hear anything interesting,I joined Steve, who was about 20 yards away. We started talking, and I was responding to something he said when his hands went up and his eyes widened. He whispered, “Did you hear that? Kent calls?” I shook my head no. We listened for a while, but probably no longer than 5 minutes.

Steve suggested we do another round of DKs to see if we could call in whatever made the sound again. I asked him to do the next round, as I my hands were stinging and sore; plus I wanted to hear them from someone with more experience. I think that, should someone have an auditory encounter, another person should take their place during a second round of DKs.

I stayed where I was standing when Steve heard the kents but was facing directly south. After 3 or 4 DKs, I heard something similar in cadence, but it had a sharper, crisper quality to it (similar to recorded Campephilus double knocks). It came roughly from the southwest. By the time Steve joined me later, I had convinced myself that it was caused by the logging that we heard going on in the distance, also to the southwest. If I mentioned hearing the DK to Steve, I probably downplayed it, blaming the logging or a falling limb; the winds were very calm at the time, and I didn’t hear any similar sounds from the logging that morning.

I have not spent much time in the field and am reluctant to place too much weight on my observations. I’d much prefer the IBWO (should it be out there) land on my shoulder “Sonny Boy” style and leave behind a fine DNA sample, after I manage to take a series of selfies!

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Don’t we all . . . or at least that we could call them in like Barred Owls.

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Barred Owl, iPhone photo by Patricia Johnson

We met up with Patricia and Steve, and Phil set up the cams; one is currently aimed at a sweet gum stub we targeted last year before losing a camera to flooding. There is some fresh woodpecker work, I suspect Hairy, on the stub, so this may be a good  time to target it. The other cam is trained on both a downed sweet gum top and a longer dead snag. Both are within the area where we’ve had multiple possible encounters recently, not far from the heavy concentration of sign found last spring.

Toward the end of the day, Phil went to do an evening stakeout in sector 1; Patricia went with him, while I took Steve a little farther north to show him a couple of the hickory stubs. In this location as well, there were a couple of recently scaled sweet gums in within 20-30 yards of the older hickories, which were similarly about 20-30 yards apart. We also examined one of the hickories Steve photographed in 2013; it was alive at the time. This one had decayed somewhat more rapidly than many of the others I’ve found, but it’s at a lower elevation relative to the nearest water body.

Steve remarked that he’s never seen feeding sign like this anywhere else, and he has spent countless professional hours in bottomland hardwood forests.

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Scaled hickory, 2013. Photo by Steve Pagans.

Frank, Phil, and John Williams will be in the search area over the next few days, so there may be another report coming soon, in addition to the post I’m planning on hickories and foraging behavior.


Trip Report: October 13-18, 2016

This was an eventful trip, with an extraordinary amount of activity on the first four days – including a possible sighting and several possible auditory encounters – and none at all on the last two. I was alone on October 13th, 17th, and 18th; Frank joined me from the 14th-16th. Conditions were generally good – light winds (strongest gust, 20 MPH, was on the 13th) and sunny or partly cloudy skies. Daytime highs were in the upper 80s-low 90s, with uncomfortably high humidity on 17th and 18th. Notwithstanding the recent flooding in Louisiana, the forest floor was dry and water levels were lower than I’ve ever seen, making it much easier to reach less accessible areas.

I found very little fresh scaling, although a tree on which we had a trail cam appeared to have been worked on quite extensively sometime after my last visit in late May. The card probably contains imagery through June and possibly into July. Unfortunately, it may have been corrupted; Frank is working on retrieving the data. If I were superstitious, I’d point to this as another case of “the curse of the ivorybill”. That aside, the paucity of fresh scaling (only a few trees with small chips consistent with PIWO work at the bases) supports the idea that bark scaling has a seasonal component that is related to breeding. This is implicit in Tanner, the limited data on ivorybill stomach contents, and in several previous posts (links).

I am somewhat hesitant to mention and describe my possible sighting and some of the other possible encounters this trip but have decided that it’s better to be comprehensive and transparent. Of all the events of the past several days, I think the double knocks Frank and I heard on Saturday were the most compelling. While my views on the IBWOs persistence are unchanged, my pessimism about obtaining conclusive documentation has grown. I may have more to say about this in a future post.

And with that, here’s the day-by-day log.

I arrived in Sector 3 at sunrise on Thursday morning and got to the ‘hot zone’ as quickly as I could.

The small pond with several scaled trees, discussed in this post, was completely dry, enabling me to look at some of the downed wood that had been in or under water on previous visits. I found a large and very interesting cavity in some blowdown. Both the shape and size are unusual and more consistent with IBWO than PIWO. (My iPhone 7 Plus’s dimensions are 6.23”x3.07”)

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I went a little farther south to the trail cam and noted that one of the target trees had been more extensively scaled since my last visit in May. The work is on the bole of this less than 1’ DBH sweet gum that had been damaged by a falling limb and has recently succumbed (photo below). There were large chips on the ground, but they did not appear to be fresh. If the scaling was done in June, as I suspect, we hope to have captured the source.

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I hunkered down and watched the trees for some time, seeing and hearing nothing of interest. When the sun was above the tree line, I ventured south and east, thinking I’d take advantage of the low water and explore some unvisited areas.

I had a possible sighting at about 9:25. I was walking south and turned to my right, looking across a clearing to a large snag that I estimated to be approximately 200 yards away (paced off at over 170 steps and later rangefindered at 160 yards). The snag in question is very close to where Frank had a sighting in March.

I texted my wife with a description that I fleshed out in an email that evening, bracketed remarks have been added for clarification.

“I saw a brilliant flash of white as a woodpecker flew up onto the tree [this was a dorsal view.] I reached for my binoculars not my camera; I think because the distance was so great. I got the bins on the bird and got them focused as it took off. I didn’t get anything like a good look, but again saw brilliant white wings with a little black. I also had the distinct impression that the bird was much too large to be a RHWO. But it was a fleeting glimpse (or better two fleeting glimpses).

I did some playback of PIWO and IBWO and had no responses.

I . . . went to the snag. There is a RHWO roost at the very top, and I saw one juvenile and another RHWO but didn’t see the head [and could not determine whether it was a juvenile or an adult]. Though RHWOs were present, seeing them at this close range made me feel even more strongly that the bird I spotted was much bigger. I can’t fully rule out RHWO, but I also find it hard to imagine that I would have been able to get any details at all such a distance unless the bird was large.” imgp3469Snag where I had the possible sighting. The bird landed on and took off from the stub at center. A Red-headed Woodpecker cavity is at the top of the left stub. My view was dorsal and from below, so the white was clearly on the trailing edges of the wings, ruling out Pileated.

This was my first possible sighting in almost three years. I was disoriented and shaken by it, as I have been with my handful of other possibles. And since it was not a good look, I can’t help but doubt myself.

In reply to my emailed description, Bob Ford had this to say:

“My ‘for what it’s worth’, I had a similar sighting once and paced it off to the same distance, then found Red-headed Woodpeckers and watched them at around that distance (maybe a little closer). Yes, can’t rule out red-headed but they look pretty small at that distance.”

As it turned out, Frank and I were able to spend some time observing Red-headed Woodpeckers in an open area at 50-100 yards. This was on Sunday morning at approximately the same time and under lighting conditions that were, if anything, somewhat brighter than those on Thursday. These observations led me to lean somewhat more strongly toward Ivory-billed Woodpecker. While the white rump of the Red-headed was easily visible at these distances, the white on the wings at a similar angle of view appears a lot less extensive and vivid than what I saw, and Red-headeds indeed look quite small.

I was able to capture a female Pileated and a sub-adult Red-headed in several frames. I’ve included a couple of the images here, both because they illustrate the size differential and because the posture of the Pileated is very similar to the posture of the bird in one of our old trail cam photos; the angle of view is different; nevertheless, it seems relevant with regard to neck length. The snag was less than fifty yards away. The first photo in the series shows the entire area. Frank measured the distance to the distant snag at right as 100 yards; the snag in the second and third images is at the left edge of the frame in the first.

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On Friday morning, Frank and I had hoped to return to the ‘hot zone’, but when we arrived another vehicle was parked at the end of the road, presumably a squirrel hunter. To avoid contact with others, we went to Sector 2 but found another vehicle parked where we were hoping to hike in. We opted to hike into Sector 3 from the south, a part of the area that we visit less frequently and that’s harder to traverse when water levels are high.

I did not note the time, but I’d estimate that it was between 9:00 and 10:00. Frank did a series of double knocks, and shortly afterwards, I heard two single knocks (Frank heard one) and then a possible distant double knock that we both heard. Later on, farther north and closer to the ‘hot zone’, he did another series, and there was a loud, close single knock, followed by what may be the longest and most agitated-sounding Pileated calling I’ve ever heard. We both found these knocks somewhat intriguing, but neither one of us thought they were compelling.

On Saturday, there were no vehicles at the trailhead, so we were able to return to the ‘hot zone’. At a little after 9:00 am, we were approaching the northernmost edge when we heard 5 double knocks from two sources to the west of us. I estimated the distance at over 200 yards, but Frank put it somewhat closer, perhaps 150. We both agreed they sounded very good for Campephilus; Frank thinks some of the best ever; he wrote: “. . . three of the first five, early on, were very crisp, clean, and woody; among the best I’ve heard.”

We stopped and waited, and heard nothing. Frank did an ADK series and got no response. About fifteen minutes later, I did another series, and this time, I heard 2-4 more double knocks. Frank was applying insect repellant, the reason for my uncertainty about the number of knocks I heard. He only heard one. We sat for another 20 minutes or so, and, after hearing nothing, proceeded south to the scaling concentration. When we reached the pond with the downed cavity, we heard another DK from the south, at fairly close range.

From there, I took Frank to where I was standing when I had the possible sighting, and he measured the distance. We then went on to explore some previously unvisited places, finding some possible cavities and starts and a little bit of older feeding sign. This part of our search area is difficult to reach and navigate unless conditions are extremely dry, and we suspect it may be where roosts are located at present. If we can visit and explore it when leaves are down, we will be able to do a more intensive search for potential roosts. This is a difficult undertaking, especially given that the big trees are more than 100’ tall.

On Sunday, we went to Sector 2, the easily accessible part of which has seen a major increase in human activity and four-wheeler use over the last three years. This is the area where the tree on the homepage is located. Because waters were so low were able to get to parts of this sector that we haven’t visited in a couple of seasons due to changes in hydrology caused by beavers and and human traffic.

I was sad to discover that what I called the kissing trees, my favorites, have separated.

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At 11:30, about 4 miles in, Frank nearly stepped on this canebrake rattler, only the third one I’ve ever seen.

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A few minutes later, a series of approximately a dozen calls from two or three sources caught our ears. We agreed on the following details: they sounded more like “yips” than “kents” (I didn’t consciously remember that Allen and Kellogg described some ivorybill calls as “yips”); they were all single notes with no variations in pitch, perhaps not as rich sounding and higher pitched than the Singer Tract recordings, but with something of their toy horn quality; the first calls came from the east and northeast, and with movement northwestward and away from us. A Downy Woodpecker called shortly afterwards; I mentioned to Frank (and he agreed) that the “yips” had a similar quality to the Downy’s “Pik”, what I’d describe in retrospect as their brevity and emphasis.

After the calls subsided, we proceeded north for another hour or so, before looping south and west. At approximately 2 PM and at about the same latititude, I heard three more calls that were more kent-like. Frank missed them; while I suspect they came from Blue Jays, I’m including them for the sake of completeness.

On the 17th, I explored parts of Sector 1 I haven’t visited before but did not see or hear anything suggestive of ivorybills. The same was true on the 18th, when I returned to the ‘hot zone’.

I don’t anticipate returning to Louisiana until sometime in December but may do another post or two between now and then.