By Isolde Raftery, msnbc.com
More than 10,000 migrating birds died of avian cholera in southern Oregon and northern California this year because of low water levels in the wetlands at a popular bird rest area, according to media reports.
“Sometimes I have seen birds literally fall out of the sky,” biologist Dave Mauser told EarthFix. “It happens that quickly.”
A cut-off water supply may be to blame, the Oregonian reported. The U.S. Bureau of Reclamation stopped water to a popular refuge for birds, the Klamath Basin National Wildlife Refuge Complex, because of light snowfall last year.
As a result, the wetlands have been flooded with about half the usual amount of water this year, Ron Cole, the refuge manager, told National Public Radio.
"You can look at a bird in the morning and it seems completely healthy and that bird may be dead in a couple of hours," Cole said.
Now volunteers are picking up dead bird carcasses to reduce bacteria in the water. Snow geese and northern pintails have been hardest hit.
The breakout began in February in Northern California and spread north to the state border. Cole believes the outbreak is slowing and that the final death toll could reach 20,000 birds.
Humans are not at high risk for avian cholera, according to EarthFix, an environmental news group affiliated with Oregon Public Broadcasting.
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