Trip Report: February 2019, Multiple Units Deployed

Since we’re now involved in a formal scientific study, I will refrain from posting about possible encounters until the end of the season. Similarly, we will refrain from using attraction methods (playbacks, kent-imitations, ADKs) while the study is ongoing. We will have a steady presence in the area but will endeavor to tread lightly.

The work on deploying the AudioMoth units began on the evening of Thursday, February 7, with an instructional session led by Tessa Rhinehart of the Kitzes Lab. In the course of this session, we decided on protocols for the deployment period to insure that there’s no confusion about the data collected.

The next morning was training day. We set out to do our first round of deployments, with rotating groups of two learning the process. I was a little unnerved when it took us most of the day to hit eight deployment points. Fortunately, the pace picked up considerably over the course of the week.

On Saturday we broke up into teams of two. A journalist joined Steve Latta and me to observe and record the deployment process. This is someone who had interviewed Frank and me and spent time in the field with us a few years ago. News of the ARU deployment renewed his interest in the story, and if all goes well his report will be airing soon. Stay tuned.

Thanks to Tessa Rhinehart – for her clear instructions, for wrangling us all, for braving the challenging conditions. Thanks also to Steve Latta, Matt Courtman, Mike Weeks, Tommy Michot, Phil Vanbergen, and Patricia Johnson for all their efforts. We covered a lot of ground and worked hard to get the job done by mid-day Wednesday. Deployments are effectively completed for the season, with units to be swapped out for review. We have opted not to spread the recording units as thinly as we had originally planned.

I had one especially interesting find, a form of foraging sign I have only seen once before, in a cluster in 2015. It’s unusual, distinctive, and though it’s somewhat outside the category I’ve suggested may be diagnostic, I think it’s likely ivorybill work and have some hope we’ll be able to resolve that question once and for all.

I found a sweet gum limb standing, embedded in the ground. It had fallen recently, as dead leaves and balls were attached; the bark was very tight; and the wood was hard, showing no signs of rot. I found a small cluster of similar work in 2015 (scroll down in both linked posts), but this type of of feeding sign is extremely unusual for the area, and I’ve never seen it anywhere else.

In 2015, I was able to identify an invasive ambrosia beetle (a tiny Scolytid) as the source of the infestation. Sweet gum is one of the main host species, and infestation, which can kill limbs and saplings but not larger trees, has become increasingly common

The chunks of bark on the ground included the largest ones I’ve ever seen from a sweet gum, the one Steve is holding below, in particular. We have documented Pileateds removing bark from sweet gums, but never in pieces approaching this size or as extensively when bark is thick and tight. While this type of work is somewhat different from what I’ve hypothesized may be diagnostic for ivorybill, I suspect that IBWO is responsible for it. We’re hoping to be able to test the samples Steve collected for DNA, so stay tuned for that.

The only close-up of ivorybill excavation is in Tanner’s dissertation, showing some small holes in a hackberry. I see a similarity between that work and some of these digs.

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

I found one especially intriguing older cavity in a sweet gum snag this trip. The shape is unusual; it seems to be an expanded knothole. The same appears to have been true of the 1935 nest cavity. The fact that this cavity is surrounded by a scaled area makes it especially interesting, though it may well be disused.

Unusual cavity in sweet gum, with scaling.

Brief Update on Another Area

Before meeting up with the team on February 7th, I spent the morning of the 6th in the vicinity of the Saucier sighting. It seemed a fitting way to remember Frank, a year and a day after his passing. As has been the case in a number of prior visits, large cavities and bark scaling are easy to find, though the scaling was not as suggestive as the best examples from our main search area.

I’m planning another post related to trail cam deployments before long.

An Exciting New Search Strategy and Two Newly Noted Calls from March 2017

Exciting news on the search front, and we’re indebted to Matt Courtman for making this happen. It is a dream come true for me, and I hope it will represent a major breakthrough in the search effort.

This post is going live on the second anniversary of Frank Wiley’s passing. I imagine that he would be as thrilled as I am about this new development.

 Matt recently reached out to the National Aviary, which is collaborating with the Kitzes Lab at the University of Pittsburgh on a variety of acoustic monitoring studies. As a result of Matt’s efforts, Pitt and the Aviary will be supplying us with 200 remote recording units, as well as technical support and processing of the data collected.

The technology has advanced considerably since the organized ivorybill searches in the early 2000s.

We plan to start deploying the units toward the end of the week, with the hope that we’ll be able to home in on potential nest/roost sites in our primary search area. Barring that, we hope the data collected will at minimum provide insight into the movements of putative ivorybills in the area. In addition, we’ll be deploying units in a number of other Louisiana locations.

In other acoustical news, Guy Luneau, whose acute hearing and outstanding ear-birding ability continue to impress, listened to the compilation clip discussed in the previous post and heard something that, to the best of my knowledge, everyone had missed. I know I had.

There are two calls toward the end of that clip (at around 2:25) that sound very similar to the “wonka-wonkas” or “wonks” (as Guy calls them to make it clear the sounds are single syllables) calls from the ’35 recordings. They’re soft, the first softer than the second, but they can be heard on headphones and both show up on the sonogram, the first very faintly. They occur approximately 3 seconds into this 16 second clip.

Several kent-like calls and two lower-pitched notes suggestive of Ivory-billed Woodpecker

I’ve extracted a relevant segment and created a sonogram using Sonic Visualizer. I have also included a bit of a sonogram from the Singer Tract showing both kents and wonka-wonkas. (The relevant segments can be found at 0:57 and 3:14 on the Allen and Kellogg recordings.) Note the smaller harmonic interval (distance between each horizontal line) in the wonkas as compared to the kents. Also note that the wonkas frequently came in pairs, with the first note considerably shorter than the second.

The two calls are at the left of the screen cap. The similar harmonic structure suggests to me that the source is the same creature. I think it also tends to further support the suggestion that these calls were made by ivorybills and tends to exclude other species.

Spectrogram showing two lower-pitched calls suggestive of the Singer Tract “wonka-wonka” calls at far left. Kent-like calls are visible farther to the right.
Sonogram of a segment from 1935 showing wonka-wonka calls on the left and kents on the right.