Second Golden Eagle Dead from West Nile virus
idfg-staff
A necropsy of a golden eagle submitted to Idaho's Wildlife Health Lab confirmed that a second golden eagle has died from West Nile virus. The eagle was found recently near Arrowrock Dam and taken to the lab for testing. Having golden eagles die from West Nile is a new twist in the spread of the virus across the U.S.
Wildlife veterinarian Dr. Mark Drew said, "We know in other parts of the country we've had problems with great horned owls and redtail hawks. We haven't seen that yet in Idaho. What we've seen here is golden eagles."
The virus first appeared in the U.S. in 1999 in New York City and has since swept across the country. The virus is carried by birds but transmitted from host to host by mosquitoes. 608 people have died from the virus, as well as thousands of horses and countless number of birds - primarily ravens, crows, magpies and certain raptors.
Since West Nile is new to North America, animals don't have a natural immunity to the virus. "Because of this, the number of species it is affecting keeps growing," said Drew. "We're up to almost 250 species of birds in this country that it's been found in."
While the virus is affecting a wide range of new species, it hasn't translated into huge die-offs in all these species. The virus primarily affects corvids, such as ravens and crows, and since its arrival in the U.S., several raptor species appear to be especially vulnerable.
If the golden eagle is one of them, Drew said, "It could become an ecological concern, and we don't really understand what the dynamics might be."
This could be particularly worrisome in southwest Idaho, which has a significant number of golden eagles and other raptors nesting and wintering along the Snake River.
To track the impact on Idaho's raptor population, Drew is working with the University of Minnesota and the USGS Raptor Biology Station at Boise State University on surveillance of raptors. "It will focus on golden eagles, barn owls, kestrels and a few other species to see if we can figure out if something is already happening, or if something is poised to happen to these populations in Idaho, " Drew said.
This surveillance will be part of a larger effort already in place to monitor distribution of West Nile virus in Idaho. For the last several years, the Idaho Department of Health and Welfare and Idaho Department of Fish and Game have worked together in tracking the rise and spread of the virus in Idaho. Part of the surveillance depends on the public to report dead and dying birds. Drew said this is basically a phone call to Idaho Fish and Game that says, "I found or saw such-and-such a bird in such-and-such a place, on such-and-such a date."
In addition, people are encouraged to submit bird carcasses to be tested for West Nile virus. This is the only way to know for sure if the virus is the cause of death.
When collecting sick or dead birds, certain precautions should be used including the use of gloves and double bagging the carcass in plastic bags. Birds should be submitted for testing within twenty four hours of death. People who have birds to submit for testing should take them to an Idaho Fish and Game office or a local conservation officer.
Dead bird reporting forms and procedures for handling the birds can be found on the Fish and Game web site: http://fishandgame.idaho.gov.