Troy Colson-KTVB

Dead barn owls can be spotted all along Interstate 84 east of Boise. The owls are killed when they fly into the path of oncoming vehicles.

BOISE -- If you drive down the interstate east of Boise you may spot some of the hundreds of dead owls that are being reported.

The owls are being hit by vehicles in unusually high numbers and so far no one is certain why such a large amount is dying.  

Barn owl deaths are becoming extremely common along Interstate 84 in southern Idaho. It tends to occur all year long, but peaks in the wintertime. And in the past couple of years the situation has gotten worse.

Experts think the owls are hunting for prey at night along the interstate -- flying low and in front of vehicles, and ultimately getting hit. 

And the large number of deaths was enough of a concern that a Boise State University professor began a small study to find out just how many were dying. The numbers are startling.

"Thousands per year seem to be getting killed, and that suggests that there are probably a lot of barn owls in our area. But it also suggests it has the potential to be a really important mortality factor for them and start to effect their population, so there might be some conservation concern for them," said Jim Belthoff, BSU biology professor.   

Boise State has three freezers full of dead owls that they've collected during the three-year study, which just wrapped up. 

Most of them are young and were healthy when they died. Some even had rodents in their talons.

The next step will be to try to minimize the deaths.

One plan is to get a nest box program going. 

Another is to seek money for highway signs that warn people about the owls -- a lot like deer crossing signs. 

Work is still being done to better determine why the birds are putting themselves in the path of vehicles in such large numbers.