Date: November 2, 2015
Source: Washington University in St. Louis
Many people remember the arrival of West Nile in North America in 1999, if only because the initial outbreak killed not just wild crows but also exotic birds in the Bronx Zoo.
In the following years, a trail of dead crows marked the spread of the virus from the East through the Midwest on to the West Coast. It took only four years for the introduced virus to span the continent.
But what happened to bird populations in the wake of the virus's advance? Were some species decimated and others left untouched? After the initial die-off were the remaining birds immune, or mown down by successive waves of the disease? Nobody really knew.
Now, a study published in the Nov. 2 issue of Proceedings of the National Academy of Sciences provides some answers. The study, a collaboration among scientists at Colorado State University, the University of California at Los Angeles, Washington University in St. Louis and the Institute for Bird Populations (IBP), is the first to fully document the demographic impacts of West Nile virus on North American bird populations.
The scientists analyzed 16 years of mark-recapture data collected at more than 500 bird-banding stations operated using the Monitoring Avian Productivity and Survival protocol developed by IBP, a California-based nonprofit that studies declines in bird populations.