Something To Crow About
Thursday, January 26, 2006
Once, the crow was viewed as a symbol of death. Now, the crow is the one dying. Its ugly song, oddly soothing to some, is muted. Over the past six years, the West Nile virus has devastated the colonies that used to gather by the thousands in their treetop roosts from October to March.
This crash may be welcomed by city dwellers who are disturbed at first light by the crow's sleep-rousing cacophony, or by the sight of a feathered mob around trash or carrion. Certainly, for vegetable growers, the absence of the crow means one less pest to worry about.
"I hate to say it, but it removes a problem," said Mark Israel, who raises organic food on a hillside farm in Gaithersburg. When he sowed beans, peas and corn, hordes of crows would show up. "At first, they would wait until the seed came up. Then they learned that when they saw tilled ground, they didn't have to wait for the seeds to germinate," he said.
Clever as they are, crows have not been able to fight West Nile like other birds. Populations continue to decline, and their absence is felt.
Carol Ghebelin and fellow birders in the Southern Maryland Audubon Society would routinely tally 1,000 crows in their portion of the Audubon's national census; last year, the figure was just 120.
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.
When they were young, McGowan put radio tags on the birds, tracked their lives and knew them as individuals. "We don't anthropomorphize them, but you can't help feel the loss of animals you have known for 10 years," he said. "Some of them, I knew their mother as an egg."
But there are signs that we may be emerging from our Silent Winter. In my garden in Alexandria, the sight and sounds of the crows have returned. Not in the same numbers, but the flock is back after a couple of winters away. They can be seen flying soon after sunrise and returning to their rookery on the other side of an urban cemetery at dusk. They are back in enough numbers to mob a resident hawk.
Israel senses the same phenomenon at his Query Mill Hill Farm. "It seems to me I see more lately."
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."
There is speculation that the crow is becoming resistant to the virus, which can sicken and sometimes kill people. "There may be some resistance developing, but the birds aren't recovering yet," McGowan said.