Friday, October 06, 2006

IBWO or young deer vocalization?

Sonograms here.

I wouldn't be a bit surprised if some of Hill et al's kent-like calls were actually produced by deer "up to one year old".

25 comments:

Anonymous said...

I wouldn't be a bit surprised if some of Hill et al's kent-like calls were actually produced by deer "up to one year old".

And there is no doubt that those deer would need a large roost hole to get in an out of the nest.

Anonymous said...

An abstract by Hill et al. (from Laura Erickson's website)

THE DOUBLE KNOCK OF CAMPEPHILUS WOODPECKERS: WHAT SHOULD AN IVORY-BILLED WOODPECKER SOUND LIKE?

We analyzed recordings of double knocks of four species of Campephilus woodpeckers: Megellanic, Robust, Pale-billed, and Red-necked. We predicted that body size would relate to knock frequency and allow us to predict the knock frequency of Ivory-billed Woodpeckers. Contrary to our prediction, there was no significant relationship between body size and timing between knocks. The second smallest species, the Pale-billed, gave the slowest knocks and the largest species, Magellanic, gave the second fastest knocks. We conclude that knock rate is shaped by factors other than body size in Campephilus woodpeckers. In all members of the genus, typical double knocks have a louder first knock than second knock. This loud-soft knock pattern also matches descriptions of the double knock of Ivory-billed Woodpeckers and should be used as a criterion in assessing putative double knock recordings in North America.


Two conclusions may be drawn:

(1) all we know about IBWO double knocks is what was written about them before the IBWO went extinct.

(2) the "science" of predicting the sounds of woodpeckers by extrapolating from the sounds that other woodpeckers make is, at best, in its fetal stage.

Anonymous said...

First, excellent website, Tom. Keep up the good work! Docmartin deserves credit for bringing attention to this possible source for at least some of Hill et al.'s "putative kent calls."

I would like to point out that this kent-like distress call given by deer is easily interpreted as Ivory-billed Woodpecker by a person looking for or expecting to find that species. Exactly that happened to my friend Donna Dittmann, who last year wrote to me describing such an experience in Louisiana. Here is what she wrote then [Sept 15, 2005]: "Here's something to consider with regard to the IBWO vocalizations, White-tailed Deer...Yesterday I encountered a 'new' sound in my yard. The sound and especially the cadence reminded me of the IBWO recordings…My bet is that it was the fawn calling for the mother (maybe vice versa, but all I've heard from does in the past are snorts). It was a fairly loud series of notes: single, then second two paired...followed by another, two more paired and a final note---a relatively long pause, then the same pattern." More recently, she told me that at first she thought someone was playing a joke on her, playing the Ivory-bill recording to see her reaction.

The paper by Richardson et al. on deer sounds suggests that one could hear this sound year-round because it is given by fawns and yearlings as well as older females. Here is the quote: "Distress calls given by fawns and yearlings of both sexes and older females are also believed to be directed nonspecifically" [follows discussion of what motivations and cues the signal may communicate; Richardson et al. 1983, Journal of Mammalogy, vol. 64, pg 247]. I think the spectrograms of many of the Hill et al.'s sounds are better matched by these deer sounds, and knowing that the sounds in life are a good match suggests these must be eliminated before drawing any conclusions or making suggestive inferences (…that they are of ivory-bills).

I too have looked at many of the putative kent calls reported by Hill et al. and compared them to the entire archived cut of Ivory-bill recordings from the Macaulay Library of Natural Sounds (MLNS). A quick comparison using Raven sound analysis software shows that the harmonic frequencies of the Hill et al. putative kent calls are not really as close a match as suggested. None sound close to the full set of kents to my ear (Two birds give over 380 kents and several bouts or rapid kents not counted over the entire cut. Given one cannot tell one bird from the other, the sample might best be treated as one; variation is slight but measurable). The Hill et al. "putative kents" show harmonic frequencies that differ from the recorded Ivory-bill souns, the frequency span of the notes narrower, and the duration considerably longer. (real IBWO: notes typically last 60 to 100 ms and have a fundamental frequency between 484 and 668 Hz (fundamentals reported by Hill et al. are 632±24 Hz, 1264±50 Hz, and 1891±68 Hz for n = 31 calls on the CLO website [not entire cut of known sounds]; FL putative kent calls: duration 210 ms ±80 ms (n = 210) with fundamentals at 748±102 Hz (n=161), 1443±220 Hz (n = 184), and 2144±334 Hz (n = 172).)

Could Ivory-bills have made a sound unknown and unrecorded. Yes, but I think that begs the question. It is important note that James Tanner listened to the entire extent of the recordings now at MLNS and commented on them. He reported that "most of the calls recorded are the ordinary kent and some of the yent-yent-yent (latter described lower and softer, and continued…given when mated birds are together). Some sounds were never recorded, and Tanner describes those. These include sounds heard at and away from the nest. For example, how the sound changes in young as they age and, significantly to my mind, a loud kient-kient-kient, which he did hear on occasion by a bird in flight. These latter calls are unreported and unrecorded by any observer or autonomous unit, which I find unlikely if ivory-bills were indeed present. So, the known variation in sounds is broader than just the 10 minutes of kents and yents that remain.

Anonymous said...

The Rotten man says...

The UEA in Norwich, England has long been a hot bed of birding activity and has produced some of the countries top birders. No suprses then that they've got in on the act and beaten Cornell and Auburn to the definitive proof

http://www.uea.ac.uk/~e039/BBC/IBW.htm

remember where you read it first...

laurancej said...

tim allwood.

'Long been a hot bed of birding activity'

what does this statement mean?

'Some of the countries best birders'

what does this statement mean?

'they've got in on the act'

what does this statement mean?

As you live in England a command of the English laugage should be your foremost consideration.

Anonymous said...

LaurenceJ,

I understood all of those - why can't you? Or are you perhaps being petty?

Anonymous said...

Nice…definitely the best fit yet…

http://deerfever.com/downloads/fawnbleat.wav

pd

Anonymous said...

LaurenceJ

those comments are in perfect English

what's your problem?


unfortunately the spoof website has been removed after some Bird Forum members' wailing and weeping and gnashing of teeth was heard all the way over in Norwich, England.

That and the veiled death threats to my friend Ilya from Choupique...

yes, read it all for yourselves.

Tim

Anonymous said...

Young Deer = Bambi?
How fitting that Bambi may actually be helping conservation by vocalizing in the underbrush. The movie Bambi is all about birth, death and re-birth and it both shocked and insprired people - just like the Luneau video.

Anonymous said...

Is it just me, or do those graphs use different scales?

I'm not sure this holds up any better than the bogus "evidnce" from Cornell.

Tom Archdeacon said...

It appears one scale is divided by 1000. Otherwise the kent-call on the right is well below human hearing range, assuming that those are also measure in cycles per second.

Tom Archdeacon said...

Looking at the original paper, the Auburn recordings are indeed in kHz.

Anonymous said...

Tim Alwood,

Thanks for some more inside information.

Aren't you the one that was so giddy with "inside information" re FL IBWOs that your "informant" was feeding you via PMs a 2-3 weeks back on BF?

You sure swizzled on that one for a while.

You can't be too bright not to see through that one quicker than you did. (though you are now trying to spin that you never believed it)

Martin said...

Sorry, yes, the deer figure vertical scale is in Hz, and the Florida 'kent' figure is in kHz, so the scales are the same. I can't find a Bambi 'bleat' soundfile on the web that exactly matches that of the Florida 'kents'. But if you ignore the extra harmonics on the Florida 'kent's (these weak harmonics would be easy to lose on a high contrast sonagram like the Bambis), the two calls are +/- spectrographically identical, and would sound the same. I would think that the null hypothesis is now that these two 'kent's in Fig. 1 of Hill's paper are young deer. Of course, if IBWOs sound identical to that, they could be IBWOs, but that's up to the watchers to prove. In the interest of politeness, I sent these thoughts to Prof Hill last week, but I imagine he's snowed under just now and haven't had a reply.

Anonymous said...

Folks, the scales are the same in the graphs that Martin provides, even though the deer paper is labeled in cycles per second (=Hz) and the Hill et al. in kHz. The frequencies do match up. Additionally, as reported above an experienced birder familiar with the recorded 'kent' calls of Ivory-bills thought the call given by the deer, probably the fawn, was strikingly similar in life.

Here are some measurements:
Distress call (fig. 1 a,b in Richardson et al. 1983 "Acoustics of White-tailed Deer" in J. Mammalogy 64: 245-252) measured from fig. 1a -- duration ~ 0.5s; harmonic frequencies (Hz) 750, 1400, 2100, 2750, 3350. The authors reported a mean duration for neonates of 0.59s (range 0.22-1.73s). In addition to recordings they made from a captive herd at Mississippi State Univ., "Distress calls were obtained also from wild fawns and older deer captured February through April 1980."

Fawn bleat (fig. 3 in Richardson et al. 1983) measured from figure -- duration ~ 0.21s; harmonics (Hz) 580, 1200, 1700, 2300, 2800. The authors report a mean and range duration 0.38s (0.35-0.41s) and mean pitch at 649 Hz (627-671 Hz).

"Putative kent" (appendix 7, Hill et al. 2006) measured from spectrogram produced with Raven -- duration 0.22s; harmonics (Hz) 577, 1106, 1667, 2211, 2772, 3354.

The spectrograms for the fawn bleat and the putative kent are close matches to my eye. From Tom's earlier post Dan Mennill said: "There's no other animal that we're aware of living in the southern forests that could produce a sound like that." (CBC Radio, 30 Sep 2006). It seems likely to me that one of these deer sounds, either the fawn bleat or distress call, could be the source of at least some of the sounds recorded by Mennill's team. We already know of potential double knock sources not eliminated. Because none of the sounds recorded in Florida are from verified, known sources, it is difficult, if not impossible, to refute their interpretation that Ivory-billed Woodpeckers produced them.

Anonymous said...

"Because none of the sounds recorded in Florida are from verified, known sources, it is difficult, if not impossible, to refute their interpretation that Ivory-billed Woodpeckers produced them."

By that logic, it's impossible for us to refute the interpretation that UFOs produced them!

You play a scientist on a blog but you need a mentor.

Anonymous said...

"By that logic, it's impossible for us to refute the interpretation that UFOs produced them!"

Thanks for the advice. But the point I made is that it is not science for Hill et al. to make a claim that can't be tested or refuted. In a way, what they have published obviates the likelihood that anyone will publish a useful counter-analysis because that will only be more speculation. Just take the information I posted and decide for yourself. The deer sounds are similar to some of the recordings, but one cannot say definitively.

Anonymous said...

it is difficult, if not impossible, to refute their interpretation that Ivory-billed Woodpeckers produced them

LOL!!

Can this farce get any more pathetic?

Anonymous said...

Man...

some of you anonymii are thick...

as if i ever believed Chewbacca or whatever his name is...

keep em sweet, reel em in and they make arses of themselves.

Just what happened. He thought Auburn were gonna release sightings of lots of birds so he let me know 'quietly' he'd just been and seen them. Then the Auburn sightings are revealed and found to be as dodgy as we all expected and he has to backtrack quickly.

easy

Tim

Anonymous said...

The deer sounds are similar to some of the recordings, but one cannot say definitively.



Our point is that the spinmeisters and peddlers at Auburn are claiming that nothing else in nature except maybe an IBWO can make those noises.

In that regard, the peddlers at Auburn have been refuted.

I wonder if they will shut up now? Doubt it.

Anonymous said...

Spin, Tim, spin.

You were like a schoolgirl on her first date when chewbacca whispered in your ear. :)

Anonymous said...

Tim,

You've flip-flopped on this issue more than anyone I know. You said something to this effect on Birdforum "I've changed my mind in light of the facts."

The "facts" was a PM. Why you believed that PM, I don't know, but sorry, I don't believe your were just "reeling them in."

Flip-Flop.

Anonymous said...

Poor Tim got swindled twice, but he's still my favorite poster on Birdforum, and if he were any more of a skeptic they would have banned him a long time ago!

Anonymous said...

In the interest of politeness, I sent these thoughts to Prof Hill last week, but I imagine he's snowed under just now and haven't had a reply.

Hmmm. I would think that shovelling snow is relatively easy for Dr. Hill.

Anonymous said...

I don't know....shovelling something though.....