Jason Smith is the range manager for the Confederated Tribes of Warm Springs. He's offered me a ride in his pickup truck to look for wild horses. It takes just a few minutes to find the first group. Then another pair. There are more around the next bend -- chestnuts, bays, Appaloosas and pintos. They seemingly graze wherever they want along the back roads of this arid reservation.

"You're looking at a mare there that probably has a foal on her. The reason she's so ribby and high backbone is poor vegetation, an overgrazed system and she may have age on her," Smith said.

The brown hills around here are grazed practically down to the nub. Smith also points out trampled, eroding stream banks.

"So that affects the fisheries and water quality," Smith said.

Other inland Northwest tribes are grappling with the same issue. They include the Yakama and Colville in Washington, the Umatilla in northeast Oregon and Shoshone-Bannock in eastern Idaho. Smith says he gets complaints about too many hungry horses from many sides... from cattle ranchers, from deer and elk hunters, and tribal members who gather edible and medicinal plants.