The Baird's sparrow, for example, requires long grass that has not been grazed, while the mountain plover lives on grazed land or in a prairie dog town where the grass is a quarter of an inch tall.

Threatened species, endangered species, and species of concern in the refuge include the black-footed ferret, black-tailed prairie dog, burrowing owl, gray wolf, grizzly bear, least tern, mountain plover, northern leopard frog, pallid sturgeon, piping plover, greater sage-grouse, sicklefin chub, and sturgeon chub.

Along the way, we keep a lookout for wildlife - bears, deer, perhaps a rare bobcat - but since this is winter, we see only birds: hawks, eagles, falcons, condor, California quail, mountain plover, owls.

These include the burrowing owl, which lives in prairie-dog burrows; the mountain plover, which prefers the close-cropped surface growth of prairie-dog towns, and, most notably, the black-footed ferret.

Other species, such as the mountain plover and the burrowing owl, also rely on prairie dog burrows for nesting areas.

Prairie falcons, northern harriers and other raptors soar along mountain ridges and canyon rims looking for feed such as migratory mountain plovers, a small ground bird.

The mountain plover is one of three species protected by the Endangered Species Act present in the Red Desert.

On June 29, 2009 the U.S. Fish and Wildlife Service published a proposed rule to list the mountain plover as threatened under the Endangered Species Act.

He'd spotted a mountain plover, a long-billed curlew, a burrowing owl and a horned lark, plus the usual assortment of lark sparrows, yellow warblers, western meadowlarks, red-winged blackbirds, crows, black terns and mourning doves.

The only sounds here are the low notes of the river's constant chatter against rock, and the higher calls of mountain plover, killdeer and the throat-clearing rasps of Clark's nutcrackers.