Minidoka NWR represents typical Snake River Plain habitat, and sage-steppe on basalt rock. The refuge covers 19 miles on both side of Lake Walcott, which is an irrigation reservoir on the Snake River. The water levels for Lake Walcott are raised in spring and kept constant all summer, then the water is dropped about 5 feet in the fall and kept low all winter.

Ornithological Summary

Minidoka NWR is an extremely important bird area because of its exceptional concentrations of diversity as well as an important site for 10 species of special concern. The refuge is a major molting area for waterfowl with a high of 100,000 ducks reported. Grasshopper Sparrow, Brewer?s Sparrow, Loggerhead Shrike, Burrowing Owls, and Ferruginous Hawk, are just a taste of the avifauna to be found here.

Lake Walcott is home to one of only two American White Pelican colonies in Idaho. Snowy Egrets, Cattle Egrets, Black-crowned Night-herons, California Gulls, Great Blue Herons, Double-crested Cormorants, Caspian Terns, Eared Grebes, Western Grebes, and Clark?s Grebes also nest colonially at this site. Additional aquatic nesting species include: waterfowl (Mallard, Gadwall, Northern Shoveler, American Wigeon, Ring-necked Duck, Redhead, Green-winged Teal, Cinnamon Teal, Blue-winged Teal, Common Goldeneye Canada Geese, among others), waterbirds (Pied-billed Grebe, American Bittern, Sora, American Coot), and shorebirds (Long-billed Curlew, Willet, Spotted Sandpiper, Killdeer, American Avocet, Wilson?s Snipe). In the fall and spring, big loafing flocks of gulls are present, mainly Ring-billed Gulls and Franklin?s Gulls, some shorebirds, and several Trumpeter Swans and Common Loons. Bald Eagles can be found here in the winter.

Loggerhead Shrike, Burrowing Owls, Ferruginous Hawk, and Bald Eagles are just a taste of the avifauna to be found here.

Conservation Issues

Introduced annual and perennial plants are a problem, especially grasses, which have lowered natural plant diversity and consequently reduced animal diversity. Also as a result, there has been an increase in fire frequency because of introduced cheatgrass. Therefore, after fires, native grasses are planted whenever possible. Past grazing reduced the native riparian trees and shrubs, which led to the discontinuation of grazing on most of the refuge in 1995 and efforts are underway to put up additional fencing to prevent grazing from trespassing livestock. In addition, refuge staff are working with the BLM to develop stock watering areas off the refuge. At the moment, the lake is zoned to keep boats away from nesting colonies and waterfowl molting areas. However, there is a potential for disturbance to nesting and molting birds if the boating area is expanded.


Grazing discontinued in 1995.
Native grasses planted after wildfires where possible.
Lake is zoned to keep boats away from nesting colonies and waterfowl.
Unfenced areas are being fenced to prevent grazing from trespassing livestock.
Working with BLM to develop stock watering areas off the refuge.


Uplands are sage-steppe; understory has been invaded by cheatgrass and some areas were planted with crested wheatgrass in the 1950/60/70s. There is a narrow fringe of trees and shrubs around the reservoir, in addition there are several islands for nesting colonial birds. The area has many basalt outcroppings and a few sand dunes.

Land Use

Lake Walcott State Park, near refuge headquarters, offers camping, fishing, picnicking, and boating.
Walcott Dam generates electricity and irrigation water.
An alternate route of the Oregon Trail is still visible on the north side of the reservoir.
Used for environmental education.
Several archaeological sites on the refuge.

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