I-84 a death strip for barn owls

BOISE — A speckled wing pokes out from the bunch grass beside I-84, wobbling in the wind that scours the scrubby high desert.

Graduate student Than Boves pulls his truck to the side of the road and picks up the lifeless bird with his bare hands, examining its dusty brown body before putting the bird in a plastic bag.

The carcass is a barn owl that likely met its end as it tracked a rodent to the pavement, reacting too late to an oncoming vehicle. It's a scene repeating itself at an alarming rate on the interstate, raising environmental, safety and agricultural concerns.

Many of these dead owls are finding their way into a freezer bursting with feather-filled plastic bags at the Raptor Research Center off Capitol Boulevard in Boise. This is where Boves, who is studying raptor biology at Boise State University, is conducting an exhaustive, low-tech study on barn owl deaths between Boise and Burley.

Up to 2,500 owls have been killed along the roadway in the past two years, and researchers are worried the deaths may be greatly reducing the population, even raising the specter of localized extinctions.

Barn owl numbers have been declining around the world for decades, but the numbers in southern Idaho are particularly striking because no one thought many lived in the area to begin with, Boves said. Southern Idaho is the northern edge of the barn owls' inland North American range, which stretches from coast to coast. In Europe, some countries with road mortality rates similar to south Idaho have seen localized extinctions.

No one knows how many of the ghost-faced owls live in southern Idaho. The birds are nocturnal and secretive, making population studies difficult, said raptor biologist Carl Marti, who has done extensive studies on the owls. But Marti said the numbers from the study likely mean local populations are being heavily affected.

"I've been rather surprised at the numbers he's been finding out there," he said.

Boves is working with BSU professor Jim Belthoff on the study and has been doing his twice-monthly surveys for two years. During that time he's found more than 800 dead barn owls. Accounting for owls he doesn't find and carcasses carried away by scavengers, he estimates as many as 3.5 times that many have been killed.

On a recent survey, Boves found about 15 owls from the edge of Boise to Burley. And that's just a piece of I-84. There's anecdotal evidence that the road mortality extends to other south Idaho roads and farther down the freeway.