Local birders have noticed a difference.
An annual survey of breeding birds, organized by the Patuxent Wildlife Research Center and dating to 1966, shows a precipitous drop in Maryland's crow population in 2004. Birders in 57 locations tracked an average of 60 in 2001. The number dropped to less than 34 two years ago.
And in large roosts in Illinois and Oklahoma, three-quarters of the crow populations have dropped dead in a single year, said Kevin McGowan, a scientist at the Cornell Laboratory of Ornithology in Ithaca, N.Y. He likens the species' devastation to the human plagues of medieval Europe. In his freezer, he has the bodies of 30 crows he has known since they were nestlings, the oldest 13 years of age.
Bird-watcher George Jett of Waldorf feeds crows and other wild birds. He says the once-large roost that inhabited woods near Routes 301 and 228 appears about a tenth its former size. Before the mosquito-borne virus arrived from the Middle East, he might have had 30 to 40 crows in his yard. "Now, I'm getting five or six," he said. "I hope the species learns to evolve with this. I enjoy crows."