RESTON, Va. (AP) -- People should stop feeding birds while scientists determine why hundreds have been blinded and killed in the Washington, D.C., region since late May, a federal agency said.
Wildlife managers in Washington, Virginia, Maryland and West Virginia have received an increasing number of reports about sick and dying birds in recent weeks, according to a statement from the U.S. Geological Survey on behalf of conservation groups in the area.
The agency said birds have experienced "eye swelling and crusty discharge, as well as neurological signs." Some have tremors, keep their heads tilted or have trouble balancing, The Washington Post reports. A definitive cause of death has yet to be determined.
Birds can transmit diseases to one another when they congregate at feeders and baths. Environmental agencies recommend basic precautions including avoiding the handling of birds but wearing disposable gloves if necessary, keeping pets away from birds and cleaning feeders with bleach.
Megan Kirchgessner, a veterinarian with Virginia's Department of Wildlife Resources, told the Post that at least 325 reports of sick birds have been collected. She said the condition appears to effect only young blue jays and grackles, not other species or animals.
"This is significant because it seems to be pretty widespread, and also it's extending for a pretty good period of time," Kirchgessner said. "And it's continuing."
Laboratories at the Geological Survey, the University of Georgia and the University of Pennsylvania have been working with the agencies in the region to determine the cause of the birds' deaths, officials said.
Kirchgessner said letting birds find their own food helps to avoid the possibility of spreading disease.
"From a veterinary perspective, especially in the springtime when food is abundant, there's no reason for those feeders to be out," she said. "And to be perfectly honest, especially in a situation like this, they can do more harm than good."