A cliff-dwelling California condor chick in Ventura County, Calif., died in late August from a West Nile virus infection. The chick is one of only four of its species born in the wild this year.
The 3-month-old bird's illness was complicated by pneumonia, according to the U.S. Fish and Wildlife Service (FWS), which is administering a recovery program for these highly endangered birds.
Knowing the species' vulnerability to West Nile virus, FWS scientists had inoculated the chick's parents with a condor-specific West Nile vaccine in 2003 and 2004.