10000 birds dead cholera 032912

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10,000 dead birds at refuges

Birds attracted to wetlands dying from avian cholera in and around refuges

by LEE JUILLERAT, Herald and News 3/28/12.

Roughly 10,000 birds, mostly snow geese, have died of avian cholera on and near the water starved Lower Klamath and Tule Lake national wildlife refuges.

Limited water deliveries to the refuges, combined with large bird migrations, are blamed for the cholera outbreak, said Ron Cole, the Klamath Basin National Wildlife Refuges Complex manager.

He said limited water deliveries to Lower Klamath last fall and this winter have dried up about half of the refuge’s wetlands.

In turn, about 2 million birds, including large numbers of migrating pintails and Arctic nesting geese, are concentrated in smaller areas.

“When you concentrate that many birds on about half of the available wetlands, you develop a recipe for an avian cholera outbreak,” Cole said, noting the bacteria that causes avian cholera spreads more rapidly in heavy concentrations of birds.

“We have not seen an outbreak of this magnitude for some time,” he said.

Refuge staff and volunteers have picked up about 3,500 birds, mostly snow geese, a long with white-fronted geese, northern pintail, American widgeon, coots, mallards, lesser scaup, ringed-necked ducks and some tundra swans.

“Picking up carcasses as quickly as we can is the best way to prevent the disease from spreading,” he said, noting volunteers are helping scoop up dead birds. “Having sufficient wetlands flooded so that birds can spread out more would be another way to minimize an outbreak.”

Cole said no significant losses have yet been reported on Upper Klamath Lake, and estimates about 10,000 birds have died on and off refuge lands.

He said scavengers, including bald eagles that feed on bird carcasses, are generally not threatened by cholera infected birds. Only four cases have been documented of bald eagles dying of avian cholera on the Klamath refuge complex.