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Scientists race to explain mysterious beak deformities spreading through crow population
By RANDY SHORE 28 DEC 2010 COMMENTS(0) THE GREEN MAN
Formerly rare beak deformities are spreading rapidly among crows in southwestern B.C. and Puget Sound, according to researchers from the U.S. Geological Survey.
.. a capture program in 2007 and 2008 revealed that more than 16 per cent of the Alaskan crow population was afflicted, "the highest rate of gross deformities ever recorded in a wild bird population."
"That’s about 10 to 20 times the normal rate," said Colleen Handel, co-author of a recent article on the phenomenon published in The Auk....
Handel and her co-author Caroline Van Hemert began to receive reports of similar deformities down the Alaska Panhandle, from the Vancouver area and communities surrounding Puget Sound in Washington state.
There are also indications the ailment, known as Avian Keratin Disorder, has affected other bird species.
...
The cause of the ailment is unknown. Possible candidates include environmental toxins, parasites, bacterial infection and viral infection.
...
Researchers working in B.C. and Washington had not recorded any beak deformities in crows before 1999, she said.
"It was a little surprising to us that it seems to be spreading. The geographic patterns suggest deformities in crows started in south-central Alaska and spread south," said Handel.
"There has been a really fairly rapid increase in Alaska and, as far as we can tell, in Puget Sound and the Vancouver area."
In one Alaskan crow population studied by the researchers, 36 per cent of the birds were afflicted, what the study calls an "epizootic cluster," an epidemic in the animal world.
...
Avian Keratin Disorder also affects black-capped chickadees in Alaska, and Handel worries it has already spread to other bird populations.
"There is every indication that the same disorder is affecting both [crows and chickadees] and we have seen similar deformities in species such as woodpeckers and nuthatches," Handel said.
...
"We are testing for a lot things simultaneously, but neither environmental contaminants nor disease has produced a smoking gun," she said.
"We are looking for a virus, but they can be very difficult to find. You can develop a test for a virus and then not be able to detect it because they mutate so rapidly."
http://communities.canada.com/vanco...formities-spread-through-crow-population.aspx
Environmental problems in the area of Puget Sound include nitrates,e-coli and fecal coliform bacteria
http://pubs.usgs.gov/circ/circ1216/images/psb_fig20a.gif
and toxins
http://www.soundtoxins.org/soundtoxins_map_sm.jpg
By RANDY SHORE 28 DEC 2010 COMMENTS(0) THE GREEN MAN
Formerly rare beak deformities are spreading rapidly among crows in southwestern B.C. and Puget Sound, according to researchers from the U.S. Geological Survey.
.. a capture program in 2007 and 2008 revealed that more than 16 per cent of the Alaskan crow population was afflicted, "the highest rate of gross deformities ever recorded in a wild bird population."
"That’s about 10 to 20 times the normal rate," said Colleen Handel, co-author of a recent article on the phenomenon published in The Auk....
Handel and her co-author Caroline Van Hemert began to receive reports of similar deformities down the Alaska Panhandle, from the Vancouver area and communities surrounding Puget Sound in Washington state.
There are also indications the ailment, known as Avian Keratin Disorder, has affected other bird species.
...
The cause of the ailment is unknown. Possible candidates include environmental toxins, parasites, bacterial infection and viral infection.
...
Researchers working in B.C. and Washington had not recorded any beak deformities in crows before 1999, she said.
"It was a little surprising to us that it seems to be spreading. The geographic patterns suggest deformities in crows started in south-central Alaska and spread south," said Handel.
"There has been a really fairly rapid increase in Alaska and, as far as we can tell, in Puget Sound and the Vancouver area."
In one Alaskan crow population studied by the researchers, 36 per cent of the birds were afflicted, what the study calls an "epizootic cluster," an epidemic in the animal world.
...
Avian Keratin Disorder also affects black-capped chickadees in Alaska, and Handel worries it has already spread to other bird populations.
"There is every indication that the same disorder is affecting both [crows and chickadees] and we have seen similar deformities in species such as woodpeckers and nuthatches," Handel said.
...
"We are testing for a lot things simultaneously, but neither environmental contaminants nor disease has produced a smoking gun," she said.
"We are looking for a virus, but they can be very difficult to find. You can develop a test for a virus and then not be able to detect it because they mutate so rapidly."
http://communities.canada.com/vanco...formities-spread-through-crow-population.aspx
Environmental problems in the area of Puget Sound include nitrates,e-coli and fecal coliform bacteria
http://pubs.usgs.gov/circ/circ1216/images/psb_fig20a.gif
and toxins
http://www.soundtoxins.org/soundtoxins_map_sm.jpg
