Ivory-billed Woodpecker (formerly updates) (5 Viewers)

[naples]

I must note that one of the four specimens that used appeared to be a juvenile female bird. This bird had a bill width at the tip of 3mm. That is smaller than I have heard for any other IBW. The bill length (I measured to the nasal feathers as opposed to the junction of the mandible) was 20-25 % less then the other four specimens. The birds overall height was about an inch shorter (mounted birds are not easy to measure exactly) than the other three.

I heard Dr. Jackson speak earlier this year, he showed a specimen that had a rounded bill tip much like a duck, thought to be a juvenile and that only over time do their bills become more sharp. Thus a long dependence on parents, perhaps another reason for low reproduction.

 

[Jesse Gilsdorf]

A correspondent, Rick Mark, who created a very nice website about Twin Swamps in Indiana passed this on to me today.

"I've been checking our Arthur Cleveland Bent book on Life Histories of birds. This book gives the former range of IBW as up the Ohio River as far as Ohio and up the Wabash as far as Mount Carmel, Illinois (familiar turf for me). It also mentions pecans as commonly found in the stomach contents of IBW. Interesting because we used to see pecan trees growing wild in the southwest tip of Indiana but not farther north."

I would suggest viewing the Twin Swamps website as the area was apparently not known to "professionals" according to Mark until Mike Homoya, a state biologist, "stumbled" on it as Mark put it, in the 1980's. The website is

http://www.usi.edu/science/biology/TwinSwamps/Wildflowers_of_Twin_Swamps.htm

It's has a good deal of information in it for those just interested in cypress swamps. He related that he never saw an ivory bill there, but saw just about anything else one might expect to find. If that swamp was not known to the state until 1980 what else was not known to the State of Indiana or other experts?

 

[Jesse Gilsdorf]

I heard Dr. Jackson speak earlier this year, he showed a specimen that had a rounded bill tip much like a duck, thought to be a juvenile and that only over time do their bills become more sharp. Thus a long dependence on parents, perhaps another reason for low reproduction.

I did a very scientific test on the bills to determine if they were sharp or if they were dull. I jabbed my thumb with each bill. I can tell you all four were quite pointy. Hard science at work, I know, but effective enough for me.

 

[fishcrow]

Some close-ups of the foraging sign that I found yesterday are posted at fishcrow.com.

 

[naples]

I did a very scientific test on the bills to determine if they were sharp or if they were dull. I jabbed my thumb with each bill. I can tell you all four were quite pointy. Hard science at work, I know, but effective enough for me.

Dr. Jackson also showed a specimen that had a 17" bill, I think upper bill, it looked like on of those long finger nails you see in the record books, long and curled, I believe it was taken in Cuba with a group of birds. It had either a birth defect or was injured the upper and lower bill didn't properly line up, and the bill just grew and grew, apperently it was feed by the group. Bill and tip size might be a result of use.

 

[fangsheath]

There appears to be a fair amount of variation in beak tip shape even among adult ivory-bills. This may be ontogenetic but in any case I think it is reasonable to expect that some ivory-bills will produce relatively narrow gouges. Certainly I would expect juveniles to do so. However, based on my model work I would say that gouge width is by no means merely a question of the shape of the beak tip in one or even two planes. It is a function of the entire 3-dimensional shape of the tip. I can fabricate two tips with exactly the same dimensions in both the sagittal and horizontal planes that will produce very different gouge widths.

 

[MMinNY]

Some close-ups of the foraging sign that I found yesterday are posted at fishcrow.com.

What are you hearing that makes you think this is pileated work, and did you measure the gouges?

 

[fishcrow]

What are you hearing that makes you think this is pileated work, and did you measure the gouges?

A few birders have seen this type of foraging sign outside the range of the ivorybill. What might be interesting is that they're all from up north. Could it be that pileateds use different foraging techniques on the tree species of the north or to get at different insect species?

I've been using the approach of going into areas where ivorybills have been encountered, covering lots of ground, and watching and listening. I haven't paid much attention to foraging sign. Now that I'm starting to think about this issue, I'm totally confused. Somewhere I read that ivorybills tend to only go for insects that are right under the bark and that pileateds bore deeper into the trunk. On the other hand, there are photos of dramatic furrows from Arkansas that are attributed to ivorybills. The ones that I found down here are so similar that I thought they must be ivorybill sign the moment I saw them.

 

[naples]

Fresh woodpecker work must = fresh beak cells.
Does anyone have some scotch tape and a microscope?
In the lab. it should be easy to determine the species.

 

[fangsheath]

Mike,

Thanks for the nice close-ups. Based on my estimate of gouge widths using your penny for scale, I would say the gouges in at least one photo are probably pileated. They appear to be generally less than 3 mm wide. (The length of the columns of the Lincoln Memorial is about 2.5 mm.) However, making such assessments from a photo is always tricky.

It isn't only the long furrows in the Big Woods that are believed to be ivory-bill work. There is bark scaling too. In both cases it is the gouge widths that give us pause. The long trenches are interesting and unusual. But without gouge widths they are no more than that. As with many of these cases, an individual tree may have been worked on by both species. So many gouges will have to be measured.

 

[Snowy1]

The second and third picture looks very familiar in the workings. The fourth picture shows beetle trails but I don't see any gouges. Are these different trees or the same ones?

The first, second and third are different. The fourth is another angle of the third tree.

On another note, while I was in the same area, I took the picture below. Looks a little strange to me, but nothing surprises me now! I'm not sure what to make of it.

 

[fangsheath]

It is not unusual for male pileateds to have quite a bit of white around the eye. This combined with the obscuration by branches is producing a bit of an odd effect.

 

[Snowy1]

It is not unusual for male pileateds to have quite a bit of white around the eye. This combined with the obscuration by branches is producing a bit of an odd effect.

Good. For a moment I thought we had ourselves a new species, perhaps one that scales bark, double-raps, and who's call is "kent" but for some reason we had never noticed it. That's a load off my mind.

 

[Billbill]

Interesting trend on one prominent "skeptical" blog... in recent weeks it has gone from allowing comments with a wide range of opinions, to allowing primarily those that concur with the host's and only a few comments with contrary opinions, to now it seems allowing no contrary comments at all. Is this a response to the CLOs recent presentations of evidence? One can only speculate...

 

[SBauer]

Interesting trend on one prominent "skeptical" blog... in recent weeks it has gone from allowing comments with a wide range of opinions, to allowing primarily those that concur with the host's and only a few comments with contrary opinions, to now it seems allowing no contrary comments at all. Is this a response to the CLOs recent presentations of evidence? One can only speculate...

Actually, it seems to me that there just aren't that many people commenting right now. Recently, there were some IBWO discussions on several state listservs. They all seemed to stop when Cornell posted the analysis. I don't know if it's taking several days for everyone to digest all that material, or if everyone had already made up their minds and therefore the analysis doesn't matter, or what.

First time poster, long time lurker,
Steve

 

[Snowy1]

Survey?

I'd like to take an informal survey if I may, completely voluntary of course!

Who on this forum has ever 1) seen an Ivorybill and/or 2) heard an Ivorybill?

By copying and pasting we could put a running list together. This is out of pure curiosity after reading your posts for close to a year now.

Survey

Snowy1:
Seen = no
Heard = I'd give it 25% chance that it was an IBWO.

Next:

 

[cts]

Dr. Jackson also showed a specimen that had a 17" bill, I think upper bill, it looked like on of those long finger nails you see in the record books, long and curled, I believe it was taken in Cuba with a group of birds. It had either a birth defect or was injured the upper and lower bill didn't properly line up, and the bill just grew and grew, apperently it was feed by the group. Bill and tip size might be a result of use.

There was a report of Chickadees exibiting the same type of defects in Alaska. It wasn't known if it was a birth defect or if the bird or birds had come in contact with something.

 

[Jesse Gilsdorf]

A few birders have seen this type of foraging sign outside the range of the ivorybill. What might be interesting is that they're all from up north. Could it be that pileateds use different foraging techniques on the tree species of the north or to get at different insect species?

I've been using the approach of going into areas where ivorybills have been encountered, covering lots of ground, and watching and listening. I haven't paid much attention to foraging sign. Now that I'm starting to think about this issue, I'm totally confused. Somewhere I read that ivorybills tend to only go for insects that are right under the bark and that pileateds bore deeper into the trunk. On the other hand, there are photos of dramatic furrows from Arkansas that are attributed to ivorybills. The ones that I found down here are so similar that I thought they must be ivorybill sign the moment I saw them.

I have seen trenches and also pits on trees within 25 miles of each other. What I do not see in areas without the IBW (or believed IBW) are the scalings were there is a great deal of bark removed, about one inch of sap wood, and grooves. That is the nice thing about living here. I keep looking for that extensive scaling and don't find it here outside any claim to IBW turf.

I find trees with multiple piletead pits in a line of varying sizes. Some are small, some are large. I have found large trenches that I believe are pileated work as well. I don't know if the area I search constitutes "Northern" location or not, because I search in an area that looks as Southern as it gets.

Keep in mind though, that the IBW (from literature) can make trenches or pits large enough to fit a shoe box in. That is a pretty good size hole!

You have to keep in mind with gouges that is still an operating theory. Despite all the hard work put into it by Fang and Steve et al until we can definately match up a bird doing the work we will be limited in what we can assuredly say is IBW or pileated. Given the size of the birds and similarities they may feed in a similar manner as well. Well, they do feed in a similar manner, they are both woodpeckers, but I am by trenching as well.

The feeding patterns will change depending on what is on the menu.

If you accept Choupique's statements concerning the bird eating terminites, and Steve Sheridan's claim that they eat red ants, (and I accept both as accurate) it is very likely that IBW will trench to get to the goodies. I expect termites and carpenter ants are on the menu as well.

If the bird is going after cerabamycid beetles I expect that they will scale the bark, take off about an inch of sap wood, and gouge out the insects from there. The insects ovapositor is going to place the larvae initially in this range of the tree, and if they lay multiple times on the same tree the buffet table is set. We get large scalings that have been observed in the Big Woods and other places. These birds can hear the beetles. Some experts on beetles say people can hear them!

Jesse

 

[fangsheath]

I have seen and heard ivory-bills on many occasions, not in the flesh of course. But to answer your question without the flippancy, again, I would have to put my encounter in the maybe category.

As for the quiet following the CLO website expansion, I guess I was assuming that most everyone who was expressing opinions about the evidence had actually looked at it carefully. Most of what is presented there was previously covered in the Science paper and in the AOU presentations. If you haven't really studied the Luneau video carefully, I can understand how you wouldn't find it compelling. It is a fuzzy video that has a passing resemblance to other fuzzy videos. I am amazed to see comments to the effect that clip #11 is difficult to distinguish from the ivory-bill video. It tells me that some people simply haven't seen or understood the CLO analysis. Clip #11 specifically has many features the ivory-bill video lacks - a clear indication of black on the trailing edge of the underwing, no indication of white on the trailing edge of the upperwing, and an extremely low wingbeat rate. I'm afraid I can't take people's criticism seriously when I see such strong indications that they haven't studied the evidence carefully. The same is true with audio evidence. Listening to the vocalizations and making a snap judgment doesn't cut it. Charif's analysis does not consist of playing the notes with known blue jays and nuthatches and saying, "Hmmm. I think I'll put that one in the ivory-bill slot." It consists of multivariate classification analysis using quantitative features of the sound structure. I have never been one to say that scientific criticism should be left to people with credentials. But throwing out half-baked snap judgments about the evidence based on nothing more than a quick impression and then using that to try to argue against money for the CLO and ivory-bill conservation will put you on my write-off list real quick.

 

[fangsheath]

Searches are already starting to move forward in South Carolina, according to an Augusta Chronicle article. The South Carolina Ivory-billed Woodpecker Working Group has already begun training volunteers to been searches next week. They are planning to have 6 2-person crews on the ground at any given time. According the article, the CLO has helped with training and a 10-week effort is planned. The Congaree Swamp appears to have the initial focus. In Georgia, specific search areas are still being evaluated.

The contact number for the South Carolina Ivory-billed Woodpecker Working Group is (843) 727-4707, ext. 214. Jennifer Koches of the USFWS is apparently involved.