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new paper on the Ivory-billed Woodpecker (1 Viewer)

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etudiant

Registered User
Supporter
The Campephilus genus is pretty well represented in the tropics, Powerful, Pale billed etc etc, so it should be fairly simple for a professional to create the graph you suggest.
 

motiheal

Well-known member
I was hoping to participate in intelligent discussions among birders who are interested in conservation. It was a waste of time.
It's not a waste of time, just does not have correct feedback from most. There are people who have learned from what you have presented.
 

motiheal

Well-known member
We truly do have a failure to communicate.
No one here ever claimed that birders were your peers, that would be the ornithological field workers.
So to persuade them, you need to get published in 'The Auk' or some similar professional journal, which incidentally are also the venues where topics such as wing flap rate deviances are likely to be very critically examined.

Here on BF you address the broader universe of mostly lay people interested in birds and nature. These are not likely to be persuaded by circumstantial evidence, rather they demand tangible proof, either good photographs or dead bodies. Do remember that John Young's photographs of Night Parrots were dismissed as hoaxes because he had photoshopped a wing covert.

The Ivory Bill is surely harder to find than even the Night Parrot, so there will be even greater unwillingness to accept its survival, especially as the bird would need to have changed its foraging strategy with the destruction of the old growth bottom land forests which it relied upon. I've seen only a handful of photos of excavations possibly done by an Ivory Bill. A surviving population should produce them continually, so their absence means the birds have adapted to their new environment or they are no longer there.

Your studies suggest they are still around, that means they must have developed a different foraging strategy. What could that be and is there any evidence for that?
Hi, not sure you got that last question answered. Their foraging strategy has not changed but the flee distance has evolved (to about 100 meters at the closest) from hunting pressures.
 

jenks86

Well-known member
Hi, not sure you got that last question answered. Their foraging strategy has not changed but the flee distance has evolved (to about 100 meters at the closest) from hunting pressures.
What hunting pressures? As far as we know, none have been hunted for over 90 years?
 

dantheman

Bah humbug
Hi, not sure you got that last question answered. Their foraging strategy has not changed but the flee distance has evolved (to about 100 meters at the closest) from hunting pressures.
Interesting ... what evidence of this is there? At 100m that would mean it quite often wouldn't be known if it was there or not to register if it was fleeing ...
 

motiheal

Well-known member
Interesting ... what evidence of this is there? At 100m that would mean it quite often wouldn't be known if it was there or not to register if it was fleeing ...
Two lines of evidence for this--
1. Flee distance is documented for numerous bird species, is roughly constant intraspecifically, and roughly correlates to bird size, larger having greater.
2. Numerous reports of roughly the 100 meter distance for IBWO (Jackson, Cornell, Hill, Michaels, personal, other).
Yes, I agree, the bird would not be seen in many cases.
 

motiheal

Well-known member
What hunting pressures? As far as we know, none have been hunted for over 90 years?
I agree, not heavily hunted for 90 years or so. But two things here--
1. we don't have a lot of data for original flee distance
2. some modern studies of literature have changed a general perception of habitat degradation being the IBWO's decline, to hunting pressures. See the work by Mark Michaels on Project Coyote website.
 

ZanderII

Well-known member
Hi, not sure you got that last question answered. Their foraging strategy has not changed but the flee distance has evolved (to about 100 meters at the closest) from hunting pressures.

I agree, not heavily hunted for 90 years or so. But two things here--
1. we don't have a lot of data for original flee distance
2. some modern studies of literature have changed a general perception of habitat degradation being the IBWO's decline, to hunting pressures. See the work by Mark Michaels on Project Coyote website.
No data to support these suppositions. Some of the last IBWOs were pursued by collectors but there is no evidence that this was a major decline driver, nor that this would have led to IBWO to become the most cryptic bird in the world.
 

motiheal

Well-known member


No data to support these suppositions. Some of the last IBWOs were pursued by collectors but there is no evidence that this was a major decline driver, nor that this would have led to IBWO to become the most cryptic bird in the world.

"Relationship with humans[edit]​

Ivory-billed body parts, particularly bills, were sometimes used for trade, ceremonies, and decoration by various Native American groups from the western Great Lakes and Great Plains regions.[103] For instance, bills marked with red pigment were found among grave goods in burials at Ton won Tonga, a village of the Omaha people. The bills may have been part of Wawaⁿ Pipes.[104] Ivory-billed woodpecker bills and scalps were commonly incorporated into ceremonial pipes by the Iowa people, another Siouan-speaking people.[103] The Sauk people and Meskwaki used ivory-billed body parts in amulets, headbands, and sacred bundles.[103] In many cases, the bills were likely acquired through trade; for instance, Ton won Tonga was located roughly 300 miles from the farthest reported range of the ivory-billed woodpecker, and the bills were only found in the graves of wealthy adult men,[104] and one bill was found in a grave in Johnstown, Colorado.[105] The bills were quite valuable, with Catesby reporting a north–south trade where bills were exchanged outside the bird's range for two or three deerskins.[4] European settlers in the United States also used ivory-bills' remains for adornment, often securing dried heads to their shot pouches, or employing them as watch fobs.[106]

The presence of ivory-bills' remains in kitchen middens has been used to infer that some Native American groups would hunt and eat the bird.[30] Such remains have been found in Illinois, Ohio,[107] West Virginia, and Georgia.[28] The hunting of ivory-billed woodpeckers for food by the residents of the Southeastern United States continued into the early 20th century,[108] with reports of hunting ivory-billed woodpeckers for food continuing until at least the 1950s.[71] In some instances, the flesh of ivory-billed woodpeckers was used as bait by trappers and fishermen.[108][78] In the nineteenth and into the early twentieth century, hunting for bird collections was extensive, with 413 specimens now housed in museum and university collections.[109] The largest collection is that of more than 60 skins at the Harvard Museum of Comparative Zoology.[110]" (Wikipedia)
 

jenks86

Well-known member
I agree, not heavily hunted for 90 years or so. But two things here--
1. we don't have a lot of data for original flee distance
2. some modern studies of literature have changed a general perception of habitat degradation being the IBWO's decline, to hunting pressures. See the work by Mark Michaels on Project Coyote website.

Thanks. Can you clarify that i am understanding correctly. The source you posted suggested that the IBW was hunted for hundreds of years, firstly by native American's then by Western Colonisers. Yet despite this hunting pressure being evident throughout most (all?) of the time the species co-habitated North America with Humans at least some IBW didn't develop or show a large flee distance. We know this as the last "known" birds were well documented, even while nesting, in the first third of the 20th century. Then around the 1930/40s, very suddenly in evolutionary terms, these same hunting pressures led to an increase in flee distances?
 

motiheal

Well-known member
Thanks. Can you clarify that i am understanding correctly. The source you posted suggested that the IBW was hunted for hundreds of years, firstly by native American's then by Western Colonisers. Yet despite this hunting pressure being evident throughout most (all?) of the time the species co-habitated North America with Humans at least some IBW didn't develop or show a large flee distance. We know this as the last "known" birds were well documented, even while nesting, in the first third of the 20th century. Then around the 1930/40s, very suddenly in evolutionary terms, these same hunting pressures led to an increase in flee distances?
There are too many guesses to comment here. What you are suggesting, can indeed happen. I can mention that a bird species, today, can have individuals who vary greatly with flee distance (we have some semi-tame Wood Ducks on a pond in Stony Brook, and I have also encountered this species as the most wary duck species on a pond). But I am certain that there are numerous modern reports, since around 2000, of the IBWO's approximately 100 meter flee distance from a human silhouette. It shows in reports. Not a huge dataset of course, but it's evident.
 

Larry Sweetland

Formerly 'Larry Wheatland'
There are too many guesses to comment here. What you are suggesting, can indeed happen. I can mention that a bird species, today, can have individuals who vary greatly with flee distance (we have some semi-tame Wood Ducks on a pond in Stony Brook, and I have also encountered this species as the most wary duck species on a pond). But I am certain that there are numerous modern reports, since around 2000, of the IBWO's approximately 100 meter flee distance from a human silhouette. It shows in reports. Not a huge dataset of course, but it's evident.
An alternative explanation perhaps being that at 100+ metres, you are more likely to misinterpret identification features that you think you've seen on a bird. If the birds had been nearer, they would have been correctly identified and not reported in the first place...
 

ZanderII

Well-known member
Occam's Razor (the simplest explanation) works for the IBWO-- the bird is just extremely hard to find.

This is your Occam's Razor right here:
An alternative explanation perhaps being that at 100+ metres, you are more likely to misinterpret identification features that you think you've seen on a bird. If the birds had been nearer, they would have been correctly identified and not reported in the first place...

The alternative explanation, that IBWOs are among us requires myriad leaps of faith.
 

ZanderII

Well-known member

"Relationship with humans[edit]​

Ivory-billed body parts, particularly bills, were sometimes used for trade, ceremonies, and decoration by various Native American groups from the western Great Lakes and Great Plains regions.[103] For instance, bills marked with red pigment were found among grave goods in burials at Ton won Tonga, a village of the Omaha people. The bills may have been part of Wawaⁿ Pipes.[104] Ivory-billed woodpecker bills and scalps were commonly incorporated into ceremonial pipes by the Iowa people, another Siouan-speaking people.[103] The Sauk people and Meskwaki used ivory-billed body parts in amulets, headbands, and sacred bundles.[103] In many cases, the bills were likely acquired through trade; for instance, Ton won Tonga was located roughly 300 miles from the farthest reported range of the ivory-billed woodpecker, and the bills were only found in the graves of wealthy adult men,[104] and one bill was found in a grave in Johnstown, Colorado.[105] The bills were quite valuable, with Catesby reporting a north–south trade where bills were exchanged outside the bird's range for two or three deerskins.[4] European settlers in the United States also used ivory-bills' remains for adornment, often securing dried heads to their shot pouches, or employing them as watch fobs.[106]

The presence of ivory-bills' remains in kitchen middens has been used to infer that some Native American groups would hunt and eat the bird.[30] Such remains have been found in Illinois, Ohio,[107] West Virginia, and Georgia.[28] The hunting of ivory-billed woodpeckers for food by the residents of the Southeastern United States continued into the early 20th century,[108] with reports of hunting ivory-billed woodpeckers for food continuing until at least the 1950s.[71] In some instances, the flesh of ivory-billed woodpeckers was used as bait by trappers and fishermen.[108][78] In the nineteenth and into the early twentieth century, hunting for bird collections was extensive, with 413 specimens now housed in museum and university collections.[109] The largest collection is that of more than 60 skins at the Harvard Museum of Comparative Zoology.[110]" (Wikipedia)
How is this different to hunting pressure on Pileated Woodpeckers? How come I can see Pileated Woodpeckers in woods in North America?

from BOW:

Effects of Human Activity​

Shooting And Trapping​

Regularly shot as food and sport by hunters early in twentieth century. Although species is protected by law, shooting is a continuing (although we hope reduced) problem (Hoyt and Hoyt 1951, JAJ) for various reasons: species (1) has been considered good to eat (Dawson 1923), (2) is a large target, (3) is a slow flyer, (4) returns with predictability to roost and nest sites, and (5) sometimes excavates on human buildings and structures.

Different groups of Native Americans hunted these birds for a variety of reasons: some believed the red crest was a talisman against all evil (Gabrielson and Jewett 1940); some used parts of woodpeckers for medicinal purposes (Bailey 1939a); some believed possession of a woodpecker head gave the owner the woodpecker's power to seek out and capture prey (Harrington in Crabb 1930).
 
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Hauksen

Forum member
Hi,

But I am certain that there are numerous modern reports, since around 2000, of the IBWO's approximately 100 meter flee distance from a human silhouette. It shows in reports. Not a huge dataset of course, but it's evident.

Amazing that there are "numerous modern reports" of the Ivory-Billed Woodpecker surviving ... I really doubt the validity of these statistics.

It might just as well be the inverse lamp post effect at work ... people only find Ivory-Billed Woodpeckers when the birds are too far away for a reliable identification.

In fact, the more "numerous" the reports are, the louder the absence of an unambiguous photograph of the claimed Ivory-Billed woodpeckers speaks against its continued survival.

Regards,

Henning
 

pileated canada bull

Well-known member
Canada
Hi,



Amazing that there are "numerous modern reports" of the Ivory-Billed Woodpecker surviving ... I really doubt the validity of these statistics.

It might just as well be the inverse lamp post effect at work ... people only find Ivory-Billed Woodpeckers when the birds are too far away for a reliable identification.

In fact, the more "numerous" the reports are, the louder the absence of an unambiguous photograph of the claimed Ivory-Billed woodpeckers speaks against its continued survival.

Regards,

Henning
Several Ivory-billeds have been seen very close, but the bird or birds being alive do not pose.
 

pileated canada bull

Well-known member
Canada
How is this different to hunting pressure on Pileated Woodpeckers? How come I can see Pileated Woodpeckers in woods in North America?

from BOW:

Effects of Human Activity​

Shooting And Trapping​

Regularly shot as food and sport by hunters early in twentieth century. Although species is protected by law, shooting is a continuing (although we hope reduced) problem (Hoyt and Hoyt 1951, JAJ) for various reasons: species (1) has been considered good to eat (Dawson 1923), (2) is a large target, (3) is a slow flyer, (4) returns with predictability to roost and nest sites, and (5) sometimes excavates on human buildings and structures.

Different groups of Native Americans hunted these birds for a variety of reasons: some believed the red crest was a talisman against all evil (Gabrielson and Jewett 1940); some used parts of woodpeckers for medicinal purposes (Bailey 1939a); some believed possession of a woodpecker head gave the owner the woodpecker's power to seek out and capture prey (Harrington in Crabb 1930).
Pileateds of course were much more numerous and the taking of 2000 birds of each species would disproportionaltey impact the rare species.
 

pileated canada bull

Well-known member
Canada
Thanks. Can you clarify that i am understanding correctly. The source you posted suggested that the IBW was hunted for hundreds of years, firstly by native American's then by Western Colonisers. Yet despite this hunting pressure being evident throughout most (all?) of the time the species co-habitated North America with Humans at least some IBW didn't develop or show a large flee distance. We know this as the last "known" birds were well documented, even while nesting, in the first third of the 20th century. Then around the 1930/40s, very suddenly in evolutionary terms, these same hunting pressures led to an increase in flee distances?
This flee distance term is new to me. Mostly it's called flush distance or flight distance. Pileateds we trapped immediately became more wary on the next try; evolution is not necessarly involved.
 

pileated canada bull

Well-known member
Canada
Hi,



Amazing that there are "numerous modern reports" of the Ivory-Billed Woodpecker surviving ... I really doubt the validity of these statistics.

It might just as well be the inverse lamp post effect at work ... people only find Ivory-Billed Woodpeckers when the birds are too far away for a reliable identification.

In fact, the more "numerous" the reports are, the louder the absence of an unambiguous photograph of the claimed Ivory-Billed woodpeckers speaks against its continued survival.

Regards,

Henning
Many people have seen and heard the birds and the sighting are concentrated in a few forests. Observer error or random acts of fraud would produce a different pattern of sightings than seen.
 
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