The Reservoir: How are birds affected?
WNV has been isolated in more than 70 species of birds found dead in the United States. Certain bird species, such as crows, appear to be much more susceptible than others. Large die-offs of crows have occurred in some areas. Mortality is less frequent in other bird species, and these birds probably serve as carriers of the WNV. Most birds are thought to be infectious for only four to five days, but some migratory birds can travel several hundred miles in this short period.
