Obviously it is in the best interest of public health to see to it that people are exposed to these viruses as little as possible. Recently, dead birds infected with the West Nile virus have been found in New York and other states, including Connecticut, Massachusetts, New Jersey, and Rhode Island. A few people living on Staten Island in New York have been diagnosed with the virus, but no human deaths have occurred yet this year. Scientists are using dead birds as an early warning sign for the presence of West Nile virus. West Nile virus infects bald eagles, blue jays, mallards, robins, red-tailed hawks, and around 15 other bird species .
Crows seem unusually sensitive to the disease.
And since crows travel less than some other birds they range only around 200 miles an infected, dead crow is a good indicator of a local virus outbreak. Mosquitoes lay their eggs in standing water. The eggs hatch into wiggling larvae that quickly grow into pupae that in turn split open to release hungry adult mosquitoes. And it's those adult mosquitoes that can transmit viral diseases like West Nile virus and encephalitis-causing viruses. Because of the West Nile virus scare, sources of standing water that could serve as mosquito breeding areas have recently been declared a public nuisance in the New York City area.