Waterfowl Production at Malheur National Wildlife Refuge, 1942-1980

Malheur National Wildlife Refuge (NWR), Harney County, Oregon, is an important breeding area for Pacific Flyway Waterfowl. Trumpeter swans (Olor buccinator), Canada geese (Branta canadensis), and 14 species of ducks nest at Malheur NWR. The refuge is one of the most important redhead (Aythya americana) nesting areas in the western United States. Malheur NWR was established by President Theodore Roosevelt in 1908, primarily as a nesting area for migratory birds. The refuge also serves as an important migration stop for thousands of waterfowl and other migratory birds. Originally the refuge was called Malheur Lake Reservation and included only Malheur, Mud, and Harney Lakes. The 60,000 acre (24,280 ha) Blitzen River Valley was added in 1935, primarily to help protect the water supply for Malheur Lake. The 22,000 acre (8,900 ha) Double-O Ranch was acquired in 1941 and smaller parcels have been added more recently. Relatively complete records have been kept of annual waterfowl production estimates at the refuge since 1942. The objectives of this paper are to summarize those historical records, describe apparent trends, and discuss some of the factors that may influence waterfowl production at Malheur NWR