Fauna Journal Entry
Illinois Birds Hurt by West Nile Virus (November 8, 2002)
Chickadees in Illinois have been harmed by the spread of West Nile virus. Courtesy National Park Service.
The population of black-capped chickadees in the Chicago area has been hurt by the spread of West Nile virus. A recent study shows the songbird's population has declined throughout the region. In parts of eastern Lake County, northern Chicago, and some southern Chicago suburbs, the birds have nearly disappeared.
The chickadee population has dipped sharply since August. Early in August, bird observers reported seeing a sudden increase in dead or sick chickadees. Around the same time, thousands of dead crows were found throughout the Chicago area. West Nile virus has been blamed for the deaths.
West Nile virus is carried by mosquitoes and can spread to humans, birds, and other animals if bitten by an infected mosquito. In many parts of the country including the Chicago area, health officials have sprayed pesticides to kill mosquitoes. But biologists are worried the pesticides are causing new problems for chickadees and other birds. The chemicals kill fish and insects other than mosquitoes, breaking food chains birds depend on for survival.
