BONNERS FERRY, Idaho (AP) — Scientists are hoping a mixture of fish guts and cow blood sprinkled liberally along the mountainous Idaho-Montana border will help them count grizzly bears.

It's an effort pushed by local government officials who suspect there may be more of these big predators in the region than their status as a threatened species may suggest.

The Spokesman-Review reports this work overseen by the U.S. Geological Survey is documenting grizzlies in a 2.4 million-acre study area stretching from the Canadian border to Sandpoint in Idaho and Thompson Falls in Montana.

There's a team of 70 field workers checking these so-called scent corrals.

Barb wire catches the bear hair, with geneticists later examining the DNA to help glean more information about the grizzlies here that are believed to number about 45 animals.