Sunday, July 01, 2007

One more woodpecker post...

...while I'm on the topic.

A question for all the "kent" hearers:

What the f--- are you folks hearing??? I mean it. I have spent tons of time in bottomland hardwood /cypress / tupelo swamps within the "historical range." I mean many months worth of time if you add it all up. All the supposed alternative sources for "kent-like sounds" have been available -- fawns, fauns, tree squeeks, blue jays, nuthatches, brakes, etc. etc. etc. Yet I have never once for a second thought I have heard an intriguing "kent" sound. Not once. Not ever. From 1974 to the present. And my hearing and expertise at bird call ID are just fine; significantly above average by most indications. So along come all you folks who stroll out into exactly the same sorts of swamps, and you start hearing "kents." All over the place. But not one of you has ever laid eyes on the source of the sound. So, really, what the hell are y'all hearing? If it's some ordinary thing, not some rare bird that only occurs in a couple of places, why haven't I ever heard it anywhere? But if it is some rare bird, why the hell haven't ANY of you ever been able to see the source? And at least some of y'all are highly experienced folks with impeccable reputations. It does not make one single bit of sense. Nobody's arguments, from "it's an Ivorybill" to "it's elvis" to "it's a tree frog" to "it's the light from venus refracted by some swamp gas" to "it's a bunch of inexperienced birders who aren't very good at discriminating natural sounds" hold water.

23 Comments:

At 9:12 AM, Blogger Mark VanderVen said...

Bill,

My hunch is that in 99% of cases the sources of kents reported in Choctawhatchee were squeaking trees or squirrels. There simply aren't bicycles in there, nor are there nuthatches. While the Blue Jays in Arkansas may "kent," I never heard anything remotely suggestive from our population in the Choctawhatchee.

Suggestions that the sources are bleating fawns may say more about the limitations of spectograms than they do about putatitve similarities between IBWO kents and bleats if the two were actually heard in the field.

 
At 10:27 AM, Blogger cyberthrush said...

"So along come all you folks who stroll out into exactly the same sorts of swamps, and you start hearing "kents." All over the place..."

Whoa Bill, methinkest you exaggerate a tad. Considering the no. of man-hours put into the search by now the number of kents actually heard by individuals remains quite few overall (more suspect kents have been picked up by automatic recording units and that would be expected), and sound in the forest, if not repeated adequately, can be hard to follow. It isn't at all odd in birding for far more common birds to be heard but not seen, especially when in the distance. In fact, I'm probably still far more concerned by the scarcity of the kents picked up thus far then by the number recorded with no sighting followup.

 
At 6:52 AM, Blogger Bill Pulliam said...

Cy -- quite a few short-term visitors, at least to the Choc, have heard "kents." And I can buy as many as 10 audio detections with no visual follow-up per one audio contact that leads to visual contact. But we are WAY beyond that 10:1 ratio with these sounds.

I'm not talking about the ARU sounds here, which are without known distance, volume, or visual context. I'm talking about flesh-and-blood birders hearing things directly with their human ears and brains. There's something real going on here. 99% of the ARU sounds may be perfectly ordinary things, but I can't see how the same applies to the direct detections. I mean, come on, can anyone really believe that Ken Able in 2007 is somehow more sugggestible and less discriminating about natural sounds than I was when I was a teenager? Yet he heard what he felt were convincingly-ivorybillish "kents," but my overeager teenage self never did. I've heard descriptions first-hand from a couple of other life-long birders with skills I am confident in who heard similar things in both Florida and Arkansas.

There is something real here, it is not a one-in-a-million freak encounter, but neither is it an ordinary sound that can be heard and misinterpreted in any swamp on any day. And no none has yet come up with an explanation that can be supported with real evidence. What we do have is a lot of speculation and "just so" stories (bicycle brakes my ass... sheesh get serious here), plus a series of good logical arguments that appear to rule out EVERY possible source of these sounds.

Maybe they are fauns (note the spelling)...

 
At 8:13 AM, Anonymous Intellectually Dishonest said...

I think the answer lies in psychology.

Whether or not one believes the Ivory-bill lives, someone searching for the Ivory-bill is more likely to detect possible Ivory-bill sounds than someone who isn't searching. Someone who truly believes the bird exists is even more likely to detect sounds of interest. I think those two statements are unquestionably true.

For example, where I live there are no elk. When I first spent time in elk country, I never "heard" a cow elk call because I didn't know what they sounded like. I either "tuned out" those cow calls or attributed them to some other unidentified source. Once I knew what they sounded like, I heard them fairly often when I was in good elk country. I occasionally mistook other sounds for cow elk calls. The most common source was trees squeaking, but there were other sources too. If the elk moved out of that area and I still believed they were there, I know I'd still occasionally "hear" cow elk calls.

Many people have laid eyes on the source of the Ivory-bill kents, and have found them to be trees squeaking, Blue Jays, nuthatches etc. I'm sure most of these incidents weren't reported. There are many other possible sources, including bicycle brakes and fawn bleats, and there are certainly other sources that haven't been thought of yet. People being people, some of these reports are certainly the result of a fertile imagination, or on occasion, lies.

So I think the answer is quite simple: The reason other people are hearing Ivory-bill kents is that they believe and hope that they will. Whenever the source can be positively identified it is from something other than an Ivory-bill.

You've seen these quotes before, but here's a few from a Julie Zickefoose article, my bold and italics:

Quoting Nancy Tanner:
You could hear them [calling] a mile away, it seemed. They were extremely loud. Very loud. The pounding was pretty darn loud, too. They are a very, very conspicuous bird. They impressed me as being extremely large and gorgeous--so much white is showing. We had located one roost hole, so we were relatively close, sitting quietly on a log in the dark, soaking wet in the swamp. The bird is the last of the woodpeckers to come out [in the morning]. He climbed to the top, pounded, and then called; pounded and then called, and the female flew over next to him, and with a great racket they flew off.

Don Eckelberry (note that this is a single bird, not a pair at a nest):

I never saw a male; this was a female. I went back and would follow her though the woods when I'd hear the double rap...The voice is like a loud HENK, like a red-breasted nuthatch, only louder. But it was not nearly as loud as the double rap. It had a double rap like ba-BOOM ba-BOOM, and that was very loud and would carry a long way. And once you'd heard that double rap, you could locate the bird.

"She came trumpeting in to the roost, her big wings cleaving the air in strong, direct flight, and she alighted with one magnificent upward swoop. Looking about wildly with her hysterical pale eyes, tossing her head from side to side, her black crest erect to the point of leaning forward, she hitched up the tree at a gallop, trumpeting all the way. Near the top she became suddenly quiet and began preening herself. With a few disordered feathers properly and vigorously rearranged, she gave her distinctive double rap, the second blow following so closely on the first that it was almost like an echo--an astonishingly loud, hollow, drumlike Bam-am! Then she hitched down the tree and sidled around to the roost hole, looked in, looked around, hitched down beneath the entrance, double-rapped, and went in."

"… One day on my way in I investigated some desultory hammering expecting to find a pileated woodpecker, but it was the ivorybill working on a broken stub not 15 feet above the ground. I watched her for a good ten minutes."

Note that these bird were located and relocated by following the sounds. Eckelberry could follow and repeatedly find a lone bird that he could observe for extended periods of time. Obviously he could have easily photographed the bird.


http://www.birdwatchersdigest.com/site/conservation/ivory_billed_jz.aspx
http://www.birdwatchersdigest.com
/site/conservation/ivory_billed_jz.aspx

 
At 9:15 AM, Blogger Mark VanderVen said...

Squeaking branches don't flush. They just stop squeaking when the wind dies down, changes direction, or has blown hard and long enough to change the physical dynamics of the tree. Hence the failure to see anything fly away.....

 
At 9:24 AM, Blogger Bill Pulliam said...

ID --

The problem I have with the psychological hypothesis is that it doesn't seem to match the observed epidemiology. There wasn't an outbreak of "kents" in the Pearl River search in 2000 in spite of high expectations. And I'll refer again to the contrast between Ken Able in 2007 versus me in 1977. If you think for a second that southern birders (especially the young hotheads) haven't been secretly thinking "Ivorybill" everytime they went into any even remotely "suitable" habitat for the last 60 years, you are very much mistaken. As for being unfamiliar with the calls, again, southern birders for the most part have had that Tanner recording of the IBWO indelibly imprinted on our brains ever since it was first published on the old Peterson's Field Guide LP about 30 or 40 years ago. No, I'm compelled to conclude that there is something real and distinctive, not just psychological and ordinary, underlying these reported sounds.

But... calling birds can be located and seen. Not always, but not never either. I could accept the "bad luck" explanation better a year or two ago. Now, like so much about this bird, it is just surreal.

 
At 10:53 AM, Anonymous C. R. said...

To Mark VanderVen,

It is reasonable to question what people are hearing. I suspect these "kents" are a variety of sounds, mostly more distant than the observer thinks. Worse, these sounds are not heard by all parties at the same time. For example, Geoff Hill describes how Brian heard kents and later Kyle says "that's what I heard" but only records two "calls" that are not certainly anything. On a number of occasions, Hill describes one person hearing something, whether a double knock or a kent, when those nearby don't hear it (e.g. with David Carr). This all sounds too uncertain, particularly whether observers are hearing the same thing at the same time.

As for deer sounds, they apparently can be kent-like in the field according to an experienced birder who participated in the Pearl River searches and knows the Ivory-bill recordings well. This birder was fooled for a reasonable period of time. See the comment here.

 
At 11:36 AM, Blogger Mark VanderVen said...

c.r.

I agree that it's reasonable to question what people are hearing.

As you can imagine, I'm quite familiar with the Auburn team's evidence!

I heard many kent-like sounds while paddling and hiking for five months in the Choctawhatchee system. Almost invariably, those were windy days. Most of the time I was able to find the source, and they were always trees. It was quite remarkable how similar some of the tree squeaks were to the recorded kents from the IBWO plush toy we had in camp.

Thanks for the link to the fawn info. It may well be, then, that some of the kents picked up by the ARUs were, indeed, fawn bleats. But if you're looking for an answer to the question, "What are those reporting kents hearing?," I can tell you with quite a bit of confidence that in most cases in the Choctawhatchee they are hearing squeaky trees.

 
At 1:07 PM, Blogger Bill Pulliam said...

I thought Dave Martin had looked at the temporal pattern of Choc ARU kents and found that it was a poor match for wind-caused noises? Something like no correlation with windy days, peak times of day not a the same time of day as peak winds, etc., if I remember right?

I've heard a million tree squeeks in my time, and they indeed can have a kenty quality, but I have never had a tree squeek experience that would have even remotely triggered "ivorybill alarms" in my head. Tree squeeks recur in a distinctive rhythm that makes them eay to nail down and identify. They are a much bigger issue for ARUs than for directly directed "kents;" I will remind y'all once again that I am NOT talking about the ARUs, just about the things people have heard in person.

 
At 2:06 PM, Anonymous Intellectually Dishonest said...

There wasn't an outbreak of "kents" in the Pearl River search in 2000 in spite of high expectations.

Of course, most rules have exceptions, but in this case I think that expectation bias explains it. In the Pearl search, searchers had high hopes (with no "proof") that a pocket of Ivory-bills had been discovered. After the Gallagher/Harrison sighting, people "knew" the birds were there, expected to hear kents, and did. The same with double knocks. And of course in the Pearl gunshots were initially mistaken for double-knocks, and I can pretty much guarantee that shotgun shots would not be mistaken for Ivory-bill double-knocks in Washington state, for example. The difference, again, is in expectation bias and not in the sound of the shots themselves. If you'll forgive the example, the same is true in Bigfoot searches. They often find evidence of Sasquatch. I never have, despite spending a great deal of time in prime Sasquatch habitat.

In the same vein, there was a huge spike in Ivory-bill reports after Cornell's announcement. Clearly this wasn't the result of spike in the Ivory-bill population, but of something else.

There are squeaky trees all over the world, yet these squeaks are only mistaken by certain people in certain areas for Ivory-bill calls. I stand by my assertion that the difference is in the mind of the listener, and not in what is being heard.

As for correlation between windy days and ARU "kents," I'd have to see the data, but since it seems clear the "kents" are coming from several sources, I'd expect to see a rather poor correlation with windy days. But as Mark said above: "I heard many kent-like sounds while paddling and hiking for five months in the Choctawhatchee system. Almost invariably, those were windy days." For him, there was a clear correlation.

Tree squeaks may or may not be in a distinctive rhythm. Each time the wind gusts a swirls in a different way, the swaying of the trees will be slightly different, resulting in subtle, or major, differences in squeaks, to the point where in some conditions the tree(s) will squeak continuously, in others sporadically, and in others not at all.

 
At 2:18 PM, Blogger Bill Pulliam said...

This comment series has been a good summary of all the standard arguments, and it still doesn't really add up. Y'all should talk to directly with some of these people who have been birding for 30 or 40 or 50 years, and who heard a sound or series of sounds that was so dead-on Ivorybillish and so unlike any of the normal sounds of the typical swamp (including tree squeeks, frogs, jays, nuthatches, deer, etc.) with which they were intimately familiar, that they practically jumped out of their skins.

A note of folklore, by the way... a "tree squeek" (note spelling) is a creature that lives in trees, looks exactly like bark, and calls mostly on windy days.

 
At 2:58 PM, Blogger Mark VanderVen said...

Good points, Bill.

A fairly experienced birder on our Auburn team heard a lengthy series of "kents" in early May. IIRC he reported having heard 30 or 40 syllables, and they didn't sound so far off to him. It was a windless day and even so the series was too rapid to have been produced by trees. This birder is from New Jersey, so is well-versed in the sundry vocalizations of Blue Jays. Unfortunately, same-day pursuit and subsequent follow-up failed to detect the sound again or reveal their source. I'm intrigued. OTOH, this birder, while quite experienced, was also the biggest optimist on our crew. And the kents were heard in the area of the swamp in which I'd seen and heard most of my Blue Jays.

 
At 4:02 PM, Anonymous David L. Martin said...

Indeed I have examined the distribution of Choc putative kents and double-knocks in relation to hourly wind speeds at a fairly close weather station. If anything there is a slight negative correlation in both cases. As a general rule winds tend to peak toward mid-day. Putative kents and double-knocks do nothing of the sort. And there is not a single putative kent or double-knock reported at night.

If trees are the source of many putative kents and/or double-knocks, then presumably we can all agree that there will not be a dramatic increase or decrease in the numbers of either from one field season to another, in the absence of some major forest change such as a hurricane? If, on the other hand, BOTH PUTATIVE KENTS AND DOUBLE-KNOCKS simultaneously decrease dramatically in frequency in a given area from one season to the next, this would strongly suggest a biological origin and in fact a fairly mobile animal that occurs at low densities.

I am looking for the best hypothesis to explain these observations, and no offense to anyone, but I will not be distracted or bamboozled by half-baked theories and clever wordsmanship which do nothing to account for patterns in the data.

As far as I'm concerned it is easy to resolve the issues of tree sounds, deer sounds, squirrel sounds, duck sounds, heron sounds, and other such confounding effects. Simply set up remote recorders in areas with plenty of deer and squirrels that probably lack ivory-bills. Science is perfectly capable of sorting the wheat from the chaff. Let's get to it.

 
At 4:31 PM, Blogger Mark VanderVen said...

I know about Dave's analyses. It's important to recognize, though, that the area within range of Auburn's ARUs represented a *tiny* section of the entire study area. One percent would be a generous figure!

I'm calling it like I heard/saw it. I followed kent-like sounds dozens of times and was often able to paddle or hike right up to the source : trees that were squeaking on windy days. My colleagues shared similar experiences. When we were able to locate the sources of kents, we didn't fill out detection forms. It's very, very important for you to note, then, that many, many detected kent sounds were not incorporated into Dave's analysis.

 
At 5:09 PM, Anonymous Intellectually Dishonest said...

I'm sure we can agree that there have been plenty of half-baked Ivory-billed theories presented in the last two years.

Were the ARU recordings made 24 hours a day, seven days a week? Were there control recordings made and analyzed from elsewhere? Were the people analyzing the recordings aware when and where they were recorded?

In any case, it seems a moot point. ARU recordings can be analyzed until the end of time and they will never convince the skeptics on their own, and for good reason. Plenty of alternate explanations have proven to account for most encounters, and the ones that aren't explained haven't been proven to be Ivory-bills. At some point that has to mean something, doesn't it?

 
At 6:27 PM, Blogger Mark VanderVen said...

And there is not a single putative kent or double-knock reported at night.

That's interesting. I've heard the same. I've also heard a kent at night.

If trees are the source of many putative kents and/or double-knocks, then presumably we can all agree that there will not be a dramatic increase or decrease in the numbers of either from one field season to another, in the absence of some major forest change such as a hurricane?

I'd agree to that, but only IF you had a significant sample size AND could document that wind conditions were similar both seasons AND the same number of ARUs were recording in the same locations during the same date range both years AND that the ARUs were randomly placed throughout the swamp AND you could assure that you were controlling for consistent interpretation of what consituted putative "kents".

If, on the other hand, BOTH PUTATIVE KENTS AND DOUBLE-KNOCKS simultaneously decrease dramatically in frequency in a given area from one season to the next, this would strongly suggest a biological origin and in fact a fairly mobile animal that occurs at low densities.

I wouldn't disagree with this if I was comfortable that all of the variables I described above were controlled for.

but I will not be distracted or bamboozled by half-baked theories and clever wordsmanship which do nothing to account for patterns in the data.

I hope that you're not talking about me! IMHO, this language (i.e. half-baked) lowers the debate. This has hardly reached the 'theoretical' level for me. Note that the third word of my first post was "hunch."

Simply set up remote recorders in areas with plenty of deer and squirrels that probably lack ivory-bills. Science is perfectly capable of sorting the wheat from the chaff.

Make sure you set up plenty of them, and perhaps strive to put them in patch types similar to what you'd find in the Choctawhatchee with similar geographic and temporalo wind patterns.

By the way, I plead guilty to hyperbole in my previous post. Based on what I was told by our sound techs, the aggregate range of the ARUs was likely ~12% of our study area at the peak of use. I'll point out, though, that ACUs were not distributed randomly throughout the forest. They were placed at intervals along creeks where the team felt they had seen and heard the bird in the past.

 
At 6:57 PM, Anonymous David L. Martin said...

I understand, Mark, and I treat your observations of the relationship between wind and kent-like sounds as valid. It might even be that the people studying the remote recordings did the same thing you did in a sense - eliminate most of the kent-like calls on windier days because they repeated frequently and were associated with less musical sounds. This would leave more isolated tree branch "kents" on less windy days which were scored as hits. That is the kind of problem that controls and double-blind protocols are designed to deal with. Nevertheless I have to look at all of the data I am currently aware of, including the spectra and temporal distributions, and try to find the best hypothesis. Are some of the sounds Dan has posted tree squeaks? I think it is pretty likely. Are most of them? I would say highly unlikely at this point. In any case I think it can be sorted out. I look forward to Dan's report.

 
At 7:42 PM, Anonymous David L. Martin said...

Mark - As for lowering the level of debate, I too have to call them as I see them, but I try not to get personal. A theory may be "half-baked," but that does not mean there is anything wrong with the baker. When Neils Bohr pointed out to Einstein that his own theory of relativity contradicted one of his criticisms of quantum mechanics, I don't think anyone thought Einstein was a dumb-ass as a result. I do think the tree squeaking falls short on accounting for many of the remotely recorded putative kents, but it is way ahead of the deer bleats and about a light-year ahead of the bicycle brakes in my book. And you have indeed baked it a little more for us here. Incidentally, I loved the wonderful photos on your blog.

 
At 11:07 AM, Anonymous IBWO Atheist said...

I see you're not posting my comments.

What a hypocrite.

 
At 11:20 AM, Blogger Bill Pulliam said...

Actually, as I explained the last time you posted here, you need to link your pseudonym to a blogger profile before I'll approve your comments anymore. There have been at least two different people posting under this same pseudonym on various blogs. Sort that out if you want to post here.

 
At 5:43 PM, Blogger Mark VanderVen said...

Dave,

I've enjoyed reading your comments here. I agree that something else may account for at least some of the kenting. As I mentioned in an earlier comment to this thread, I'm quite intrigued by the reports of a series of moving kents near an old oxbow in the northern part of our study area by one of my colleagues. It was in an area of the swamp where we hadn't set up listening stations, so there was no recorded sound data to corroborate whether or not it was a recurrently produced noise. Whatever they were, I sensed that my colleague felt that they were neither squirrel chucks nor squeaking trees.

 
At 6:29 AM, Blogger Steve said...

Hi Bill,

Back in October 2006 I was on my way from Athens to a meeting in Panama City. I stopped at a power line cut on the Choctawhatchee (north of the hot zone). It wasn't too long before I heard very interesting kent calls. A lot of them. They were coming from my side of the river, just north of the power line cut. I was cursing my lack of recording equipment. After about 30 seconds or so I watched as 2 blue jays flew out of the woods making that same call. It was the first time I had heard blue jays making that type of call. I've related this story before and many people say, 'well, there you go, they must have been imitating the IBWOs'. I think that is debateable. But, I just wanted to relate that there are jays in that system that fooled me and probably have fooled others.

 
At 2:39 PM, Blogger cogresha said...

I was down there for a week and never heard what I thought was a kent call. So us short timer, non-natives can not hear stuff with the best of them!

 

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