There has been an unprecedented number in the death of bald eagles in Utah the months of November and December. It has happened near the Great Salt Lake area where thousands of eared grebes migrate. Although the migration of eared grebes is a common for the area, the numbers of bald eagles killed is not. It is believed that the West Nile virus is to be the blame for the resent deaths in bald eagles, however other test are being performed.
Bird deaths that are tied to the West Nile virus usually occur in the warm months when mosquitoes are more active, which is the primary vector. However the extended period of warmer months that Utah has experienced this year gave the mosquitoes a long breading time. Scientist are not capable of proving if the eared grebes came into Utah infected with the West Nile virus or if they were infected when they migrated to Utah. All that has been confirmed is that the recent deaths of the bald eagles have been due to the West Nile virus. According to global animal the West Nile virus is responsible for at least twenty-seven bald eagle deaths and five contaminated eagles. It is thought that the bald eagles contacted the virus by feeding on the carcasses of the bird known as the eared grebe. According to global animal nearly twenty thousand of eared grebes have died since November outside the Salt Lake City, making it the biggest outbreak North America has seen thus far. Seeing as bald eagles are scavenger birds they would have more than likely feed on the eared grebes within days of them dyeing and that is how the virus was transferred to the bald eagles.

References www.globalanimal.org www.publicnewsservice.org
www.wildlife.utah.gov