Important Bird Areas

Benton Lake National Wildlife Refuge

Montana

Benton Lake National Wildlife Refuge is dominated by native shortgrass prairie and seasonal wetlands. The refuge is located on the western edge of the northern Great Plains about 80 km east of the Rocky Mountain Front and only 19 km from Great Falls, the third-largest city in Montana. The lake itself is a shallow wetland created by the last continental glacier. The lake is a major stopover site for migrating waterfowl and shorebirds as well as a nesting site for waterfowl and wading birds. The surrounding uplands support several grassland species of conservation concern.

{link:For IBA map, click here.|http://mtaudubon.org/birds/documents/bentonlake.web.pdf}

Ornithological Summary

During spring and fall migration, up to 150,000 ducks, 25,000 geese, 5,000 swans, and as many as 50,000 shorebirds use the refuge. Because of the concentrations of migrating shorebirds, the Western Hemisphere Shorebird Reserve Network recognizes Benton Lake as a site of Regional importance.

During an average breeding season, 20,000 ducks are produced, and several thousand pairs of Franklin's Gulls nest here. Numbers of breeding Chestnut-collared Longspurs exceed the threshold for an IBA of Global significance. In total, 240 bird species have been recorded on the refuge, nearly 90 of which are known to breed.

Conservation Issues

"Heavy metal contamination of Benton Lake Watershed and the water pumped to the refuge exists. Selenium accumulations in marsh sediments and biota originate on private land farmed for dry land crops, primarily wheat and barley, where summer fallow farming is practiced. Research on Selenium cycling and water management that incorporates a natural 'drought effect' for the refuge marshes will minimize the threat to wetland birds." (Quoted from threats write-up for the refuge on the Western Hemisphere Shorebird Reserve Network's Web site.) Botulism kills large numbers of grebes and waterfowl in some years.

Habitat

Slightly more than half of the refuge consists of marshy wetlands and lakes. The herbaceous component includes native prairie, crested wheatgrass, dense nesting cover, and other non-native grasses. About 1% of the refuge is in shelterbelts of Caragana.