Silent spring

And summer, fall and winter thanks to Avian flu and West Nile virus:

WASHINGTON, May 17 U.S. researchers have determined the West Nile virus has apparently caused the continental-scale decline of seven species of birds across North America.

The finding by Shannon LaDeau and colleagues at the Smithsonian Institution in Washington is said to be a stark example of the potential havoc that can be wreaked by invasive species, and should impact future conservation strategies.

Researchers used 26 years of Breeding Bird Survey data to determine the impact of the West Nile virus on 20 North American potential bird hosts. They found declines in seven species from four families, including the American crow population, which has dropped by 45 percent since the virus emerged.

If you see any dead birds and you feel it might be a disease that killed them, this site, although set up for tracking Avian flu, offers you a way to report it. A suggestion: Do not handle the dead bird without precautions.

The migratory routes of birds which may carry the virus: