The Lahontan Valley is a surprising wildlife oasis in the Great Basin Ecosystem. Annually, over 250,000 ducks, swans, and geese are attracted to Stillwater Complex when water conditions are right. Designated as a Globally Important Bird Area by the American Bird Conservancy, and a site of the Western Hemispheric Shorebird Reserve Network, and Stillwater Refuge is a designated National Audubon Society Important Bird Area. Thousands of American Avocets, Long-billed Dowitcher, Black-necked Stilts, and a variety of sandpipers pass through in what has been termed a true "wildlife spectacle". The Stillwater marshland has attracted some rarities as well. White-winged Scoter, Stilt Sandpiper, Brown Pelican, and the Pomarine Jaeger are a few avian species which have made a special appearance.
Kit fox, present but hard to view, are year-round residents. Mule deer, coyote, and quail are often seen along refuge roads. An occasional mountain lion ventures into the valley and through the marsh in its search for prey. A variety of lizard species and kangaroo rats leave their tracks in desert sand amidst greasewood shrubs. The White-tailed Antelope Squirrel is one of the few rodents easily seen as it darts between bush and under fence. Rabbits (Cottontail and Black-tailed jack) abound.
Winter finds Tundra swan, Bald and Golden Eagles, Rough-legged hawks, Loggerhead Shrike, and Prairie Falcons circling over the area. Egrets and herons are quite often seen overwintering. The Black-billed Magpie is a year-round resident.
Early spring boasts an onslaught of tens of thousands of returning migrants. Snow Geese, Canvasback, Northern Pintails and Green-winged and Cinnamon Teal begin to arrive in late February. American White Pelicans begin to return to find nesting habitat on Anaho Island National Wildlife Refuge in Pyramid Lake. April finds the resident waterfowl nesting and shorebirds returning in significant number. In the water, birds such as the Clark's or Western Grebe and Ruddy Duck put on their courting "shows". Long-billed Curlew, Swainson's hawks and brightly colored passerines such as Bullock's Orioles, Black-headed Grosbeaks also arrive and begin to nest.
In early May, summer colonial nesting birds including White-faced Ibis, Snowy, Great, and Cattle Egrets, Forster's Terns, and Burrowing owls are nesting. Beginning in June the late arrivals include the Common Nighthawk and a variety of flycatchers. Yellow-headed Blackbirds, Marsh Wrens, Sora, the secretive American Bittern and Virginia Rail can be seen among the tule and cattails of the marsh.
August begins the fall migration with shorebirds such as Black-necked stilt, Yellowlegs, Long-billed Dowitcher and sandpipers trekking south. Waterfowl begin arriving in September. When cold weather arrives, usually October timeframe, White-crowned Sparrows, and chickadees seek out the warmer lower altitudes.