The dead bird toll from an avian cholera outbreak just east of the Tri-Cities is approaching 2,500 birds.
However, U.S. Fish and Wildlife Service picked up fewer birds in the last three days, said Faye Healey, wildlife biologist for the Mid-Columbia River National Wildlife Refuge Complex. Collecting dead birds appears to be helping control the outbreak, she said.
Crews are picking up birds by their heads to make sure that the mucus characteristic of the disease does not spread into the wetland and leave bacteria. Birds are being incinerated soon after they are collected. Humans are not at high risk of infection.
U.S. Fish and Wildlife Service picked up 111 birds through the weekend and Monday on the McNary National Wildlife Refuge and the nearby river, Healey said.
Washington State Department of Fish and Wildlife workers picked up about 375 birds at ponds on private property east of Burbank on Monday. They had collected about 1,100 birds there late last week and federal crews previously had collected about 850 dead birds in about a week.
Most of the dead birds collected are ducks, particularly the mallards common to the Mid-Columbia.
Avian cholera is caused by a bacteria that is highly contagious and spreads quickly through bird-to-bird contact, ingestion of food or water containing the bacteria, or scavenging of infected carcasses. Infected birds may be lethargic and swim in circles or fly erratically.
They may die within as little as six hours after infection.