At least 10,000 migrating snow geese and other waterfowl have died this spring at drought-plagued Lower Klamath and Tule Lake national wildlife refuges along the Oregon border with California.
Biologists are calling the avian cholera outbreak one of the biggest drought-related die-offs in the refuges' more than 100-year history.
"We're going to estimate about 15,000 dead by the end of the outbreak," refuge manager Ron Cole said.
In an area that's increasingly stricken by drought, Cole said something needs to be done to protect the birds, and he warns of a more and larger die-offs in the years to come if the refuges don't get increased water allocations as promised in a settlement that also includes plans to tear down four dams on the Klamath River.
Cole said cholera kills ducks and geese nearly every year, as the migrating birds congregate on the refuges, which they use as a feeding and resting point on their journey north.
But Cole said this year is especially bad since the refuges' marshes have been scaled back to half their normal size by of a lack of water.
Since early March, 2 million migrating birds have been loafing and feeding in dense numbers on what open water was left, easily spreading the disease among the densely packed flocks.
The U.S. Bureau of Reclamation cut off water to the refuge on Dec. 2 due to low snowpack levels and expected low inflows to Upper Klamath Lake, said Kevin Moore, a bureau spokesman.
He said the bureau has to maintain water levels in Upper Klamath Lake under agreements to protect the endangered lost river and short-nosed suckers.
In addition to maintaining the level of Upper Klamath for the suckers, the bureau also has to deliver water to area farmers who have contracts with the bureau.
At the same time, water managers have to make sure they keep enough water in the Klamath River to support the endangered coho salmon.
Cole said the majority of the dead birds are snow and Ross's geese. But a larger than normal flight of northern pintail ducks also suffered die-offs. He said refuge employees and volunteers have picked up about 4,000 dead birds to help stop the disease from spreading even more. Many others became food for bald eagles and other raptors that dine on the birds. They don't seem to be susceptible to the disease, Cole said.
While it might mean extra food for birds of prey, Cole said the die-off could be a harbinger of things to come at the refuge complex if it doesn't soon get water rights.
John DeVoe, executive director of WaterWatch of Oregon, blamed the dead waterfowl on politics.
"These refuges are too important to become a sacrifice zone for failed state and federal policies," DeVoe said. "Ensuring Tule Lake and Lower Klamath national wildlife refuges have an adequate supply of water, and that commercial agribusiness doesn't displace wetland habitat on these refuges, are critical steps to protecting the Pacific coast's migratory waterfowl populations as well as restoring the Klamath's struggling native fish."
(Contact Damon Arthur and Ryan Sabalow of the Redding Record Searchlight in California at DArthur@redding.com