Trapping hawks to study West Nile

CANYON COUNTY - James McKinley would be the last person to brag about it, but he's about as good as it gets when it comes to catching birds of prey.

"He knows the wind, the light, the background; he's a super trapper," Bill Mattox said.

McKinley and Mattox are wildlife researchers who specialize in birds of prey. One of their current projects, tracking the progress of West Nile virus through Southwest Idaho's Swainson's hawk population, has brought them to a rocky field outside Caldwell.

With Mattox assisting, McKinley attaches small black nets to poles he's driven into the ground near a tree. High in its branches is a nest containing young Swainson's hawks.

"When it happens, it will happen fast," he says.

McKinley is, among other things, a raptor rehabilitator. In a cart in his ancient Suburban is a great horned owl that can't live in the wild because of an old injury. McKinley attaches it to a stake driven into the ground behind the nets. It can't fly but is free to move short distances. The idea is to trick the hawk into flying into the nets while trying to drive away the owl.

"It won't attack the owl," McKinley said. "I wouldn't be doing this if it did. Most of the year I feed him and he just hangs out. He has a good life. The hawk doesn't see him as prey; it sees him as an adversary. It will try to frighten him away, but there's never any contact."

He and Mattox watch from the Suburban as the mother Swainson's hawk circles, lands in the tree and makes two abortive dives at the owl - evading the nets. Then, out of nowhere, its mate swoops down and into the trap. Drag lines keep it from flying away.

The men gently free the hawk, hood it to keep it calm and begin the scientific part of the catch. They weigh and measure the bird, which McKinley had previously banded, and draw a small sample of blood. The hawk doesn't fight them at all, even after the hood is removed. When McKinley releases it, it returns to circling high above them, seemingly unfazed.

Their work is part of a cooperative research project by the Idaho Department of Fish and Game, the Wildlife Health Lab, the U.S. Geological Service, BSU's raptor research center and the University of Minnesota.

"When West Nile came from Africa to North America, it affected a plethora of species it hadn't before," Fish and Game veterinarian Mark Drew said. "If we can understand how and why it affects Swainson's hawks, which are very sensitive, we might be able to find a way to help protect them and other raptors."

Swainson's hawks were chosen in part because McKinley and Mattox have been researching them for years and had information from them before West Nile reached Idaho.

"It's one of the few cases I know of in which we have solid data from the pre- and post-West Nile incursion," Mattox said.

With luck, the research might one day lead to a vaccine.

"There's a horse vaccine that's been used for birds," Drew said. "Whether this work could lead to a better vaccine for birds is a question. But it's our hope."

For a state that's home to one of the world's densest concentrations of raptors, that would be significant.

Is a vaccine for humans a possibility?

"Maybe," Drew said. "That depends in part on how much disease the virus creates in humans. If it's significant enough that the vaccine companies could recoup their costs, it's possible. You can argue what constitutes significant, but numbers aren't everything. If you're the one who gets seriously ill, it's significant."

Tim Woodward: 377-6409