Ivory-billed Woodpecker (formerly updates) (2 Viewers)

[IBWO_Agnostic]

Maybe someone else has more details of this, but I have heard that it is possible for ducks in flight to produce a double-knock. I THINK it has to do with their wings colliding with other ducks, but I could be wrong. Has anyone else heard this theory?

 

[Curtis Croulet]

Maybe someone else has more details of this, but I have heard that it is possible for ducks in flight to produce a double-knock. I THINK it has to do with their wings colliding with other ducks, but I could be wrong. Has anyone else heard this theory?

I haven't heard that theory, but, even if true, it would have no relevance to the Ivory-bill double-knocks.

 

[SBauer]

I haven't heard that theory, but, even if true, it would have no relevance to the Ivory-bill double-knocks.

I don't disagree with you, but perhaps some explanation on why you feel this way would be useful. You're just going to get trolls otherwise.

 

[Curtis Croulet]

I don't disagree with you, but perhaps some explanation on why you feel this way would be useful. You're just going to get trolls otherwise.

As I understand it, the duck-wing "knocks" proposed by IBWO_Agnostic are random collisions of wings between ducks flying in close proximity, which one would expect to occur in single, double, triple or other multiple combinations, with no predictable interval between knocks. "Ivory-bill" double knocks occur with a predictable interval between each knock. Gallagher mentioned the interval the other night, but I don't remember what it is. Also, colliding duck wings would probably be distinguishable from "Ivory-bill" double-knocks with analysis of their sound spectrum, even if they are not distinguishable by ear (which I suspect they are). Also, if the ARUs were recording duck-wing "knocks," one would predict that they would also pick up a significant number of duck vocalizations at the same time. Maybe they have. There's a Gadwall on one of the recordings on the Cornell website -- one isolated "quack." Also, are ducks particularly concentrated in areas where Ivory-bills have been sighted?

 

[jurek]

Maybe someone else has more details of this, but I have heard that it is possible for ducks in flight to produce a double-knock.

Never heard and never heard ducks knocking - outside Donald Duck cartoon.

 

[jurek]

In addition, he mentioned that he (or the team?) have three cameras that take pictures at four-second intervals of candidate roost holes in the morning and evening.

Firends who study hole-nesting birds in natural forests say that most tree holes are too shallow for a bird or are just foraging holes without any depth. Only way is to climb a tree with catclaws and check.

I also wonder what could be found inside? Lost feather would be definite proof of IBWO thanks to DNA analysis.

 

[IBWO_Agnostic]

As I understand it, the duck-wing "knocks" proposed by IBWO_Agnostic are random collisions of wings between ducks flying in close proximity, which one would expect to occur in single, double, triple or other multiple combinations, with no predictable interval between knocks. "Ivory-bill" double knocks occur with a predictable interval between each knock. Gallagher mentioned the interval the other night, but I don't remember what it is. Also, colliding duck wings would probably be distinguishable from "Ivory-bill" double-knocks with analysis of their sound spectrum, even if they are not distinguishable by ear (which I suspect they are). Also, if the ARUs were recording duck-wing "knocks," one would predict that they would also pick up a significant number of duck vocalizations at the same time. Maybe they have. There's a Gadwall on one of the recordings on the Cornell website -- one isolated "quack." Also, are ducks particularly concentrated in areas where Ivory-bills have been sighted?

Like I said, I don't have much detail, but I do believe that when we are talking about pulling out a few seconds (knocks and kents) out of tens of thousands of hours (I heard 19,000 at one point last year), it's possible to get pretty much anything. Curtis, do you know for sure that the sound spectrum is different? Do you know for sure that the time between knocks is never duplicated (in 19,000 hours) by something other than IBWOs? See there's the rub in this whole thing, when we are reduced to trying to make non-definitive evidence definitive we really are grasping at straws.

I wish I could track down the info. I thought some of the duck wing knocks were recorded in Texas, but again it's all fuzzy (and Google is no help..in this rare case)

 

[Curtis Croulet]

Like I said, I don't have much detail, but I do believe that when we are talking about pulling out a few seconds (knocks and kents) out of tens of thousands of hours (I heard 19,000 at one point last year), it's possible to get pretty much anything. Curtis, do you know for sure that the sound spectrum is different? Do you know for sure that the time between knocks is never duplicated (in 19,000 hours) by something other than IBWOs? See there's the rub in this whole thing, when we are reduced to trying to make non-definitive evidence definitive we really are grasping at straws.

I wish I could track down the info. I thought some of the duck wing knocks were recorded in Texas, but again it's all fuzzy (and Google is no help..in this rare case)

They have many more "kents" and knocks than are on Cornell's website. Sure, it's possible that some duck wing "knocks" could create the right interval. It would be a matter of chance -- but I thought I already said that. I don't know that a spectral analysis would show the difference, but I predict that it would, since the process that produces the sound is fundamentally different. Also, Cornell has never claimed with certainty that these sounds are from Ivory-bills. That's part of their research, to look for other possibilities.

 

[Andigena]

Maybe someone else has more details of this, but I have heard that it is possible for ducks in flight to produce a double-knock. I THINK it has to do with their wings colliding with other ducks, but I could be wrong. Has anyone else heard this theory?

Never heard of duck wings "knocking"---frankly, it sounds preposterous to me. I jump shoot ducks (mostly mallards, sometimes Canada geese) and they come up off the water in a panic at close range--often very close together. I've never heard anything but wingbeats. Have you ever held a duck wing in your hand? It is very light, flexible, soft......how is that going to make a loud, far carrying sound that Tanner said could be imitated by banging a large stick on a hollow log?????.

Frankly, I think you either believe people who have heard double knocks or you don't. ...Marshall Iliff, a bird-tour leader familiar with Campephilus woodpeckers in the tropics, heard multiple double knocks, from various directions on 9 November, 2004.

Another thing I find interesting is how everyone talks about Gene Sparling, Gallagher and Harrison as being the key IBWO observers. In my mind, Melanie Driscoll, Casey Taylor, and Mindy LeBranche are much more important. They weren't personally dedicated to finding ivory-bills, they all had looks through binoculars, Casey (especially) noted multiple fieldmarks--and they all are bird science professionals. Mindy, who has a Ph.D. in ornithology (years of research on RedCock woodpeckers) didn't believe IBWO even existed. She has more credentials than ANY of the others, by far. In fact, in my view, she has more credentials than any of the "birdwatcher doubters"--none of them have a doctorate in woodpecker research. The evidence of their observations, irregardless of the video, should not be relegated to obscurity.

 

[Curtis Croulet]

Mindy, who has a Ph.D. in ornithology (years of research on RedCock woodpeckers) didn't believe IBWO even existed. She has more credentials than ANY of the others, by far. In fact, in my view, she has more credentials than any of the "birdwatcher doubters"--none of them have a doctorate in woodpecker research. The evidence of their observations, irregardless of the video, should not be relegated to obscurity.

Gallagher enjoys telling Mindy's story. She was a total skeptic when she went to Arkansas. Then she saw one. That evening she's saying she's "99% sure" she saw an Ivory-bill. Tim says, "What's this 99% @#%? What's the remaining 1%?" Mindy says, "Because it's frickin' extinct!" (I'm repeating this from his talk, not from the book.)

 

[martin kitching]

Casey (especially) noted multiple fieldmarks...

...and switched her video camera into playback mode as she approached the area where she had heard double-raps. Thus ensuring that the multiple fieldmarks she noted weren't backed up by any firm evidence. Bad luck, that.

martin

 

[Big Phil]

Lost feather would be definite proof of IBWO thanks to DNA analysis.

Would it?. Weren't there some antics in florida with a feather before?.

 

[70ivorybill78]

Regarding the "knock" of duck feathers.

I am certainly no expert on various duck species, but have the following observations. In having raised wild mallards and heard/seen them fly at close range on many occasions, I have never heard anything from their wings that would approach a double knock sound.

Regarding pigeons, I have heard very pronouned loud "claps" from their wings upon takeoff, put again, nothing that imitates the Cornell double raps.

 

[jurek]

Would it?. Weren't there some antics in florida with a feather before?.

Sorry - what antics?

 

[Big Phil]

Sorry - what antics?

If I remember right Heinzmann et al found a feather in a cavity at which they observed IBW. But got slapped down because the same feather was missing from a specimen in the state.

 

[jurek]

If I remember right Heinzmann et al found a feather in a cavity at which they observed IBW. But got slapped down because the same feather was missing from a specimen in the state.

With DNA methods similar to paternity tests, it is easy to check both species and individual of the feather. If the feather was from stuffed specimen, DNA would be identical.

 

[Edward woodwood]

99%?

why the doubt

if i saw one and noted the fieldmarks CLEARLY IN MY NOTEBOOK, i would be 100%. How come people hear double knocks from various directions yet the bird remains impossible to see?

fuzzy videos
fuzzy sightings
fuzzy logic

what was the 'official' respone to Driscoll's, Taylor's and Lebranche's sightings? They aren't accepted by BirdLife International for example.

Tim

 

[IBWO_Agnostic]

I'm hesitant to belabor the point about the ducks double knocking but I believe it was not an individual duck doing the noise but it had occurred when a big flock gets up, they are in a dense flock and the wings from two different birds hit each other creating the sound. I would imagine it would be the bones knocking together. I know it sounds far-fetched that's why I was soliciting input. I think we can summarize by saying no one here has ever heard about it, nor does it sound likely to anyone here.

I'll leave it at that (unless I hear something else about it).

BTW...good intelligent (and civil) discussion on ID-Frontiers
http://www.birdingonthe.net/mailinglists/FRID.html

 

[SBauer]

99%?

why the doubt

As has been stayed previously, "That evening she's saying she's "99% sure" she saw an Ivory-bill. Tim says, "What's this 99% @#%? What's the remaining 1%?" Mindy says, "Because it's frickin' extinct!"

 

[Edward woodwood]

As has been stayed previously, "That evening she's saying she's "99% sure" she saw an Ivory-bill. Tim says, "What's this 99% @#%? What's the remaining 1%?" Mindy says, "Because it's frickin' extinct!"

you've directly quoted me there

have a look at what i said again...

was she sure or not then?

this is how these things develop into folklore.... and we are also discussing comments that are currently no more than 'hearsay'

Tim