Snake River Birds of Prey: The Richest Raptor Canyon on Earth
Near Boise, Idaho
Thirty-five miles south of Boise, the Snake River cuts through the high desert in a canyon seven hundred feet deep, and the cliffs above the water hold the greatest concentration of nesting raptors anywhere in North America, and perhaps the world.
Every spring, more than seven hundred pairs of hawks, owls, eagles, and falcons arrive to nest in the basalt crevices and ledges of this canyon. Prairie falcons, ferruginous hawks, red-tailed hawks, American kestrels, Swainson's hawks, great horned owls, and golden eagles, all of them drawn here by the combination of sheer cliff face for nesting sites and the vast surrounding plain, which is home to one of the highest densities of Townsend's ground squirrels anywhere. The squirrels are the key: abundant prey within gliding distance of secure nests.
Biologists began documenting the population in the nineteen forties. Morley Nelson, a Boise falconer and wildlife filmmaker, spent decades photographing and advocating for the canyon. He made the case to Congress that this stretch of river was unlike anything else on the continent, and in nineteen ninety-three Congress designated it the Snake River Birds of Prey National Conservation Area, covering nearly five hundred thousand acres.
The canyon is also ancient human ground. People have lived along these walls for twelve thousand years, and petroglyphs carved into the boulders at the canyon bottom are among the oldest surviving images in Idaho. The Oregon Trail ran along the canyon rim, and emigrants crossing this section of the Snake River Plain left accounts of the birds wheeling overhead, which they found unsettling and magnificent in equal measure.
