The Raft River/Curlew Valley IBA consists of sagebrush/grass rangelands within the Raft River and Curlew-Juniper Valleys in south-central Idaho. In particular, it includes the areas along alluvial fans, bajadas, and flats adjoining the Jim Sage, Cotterel, and Black Pine Mountains. This site is highly important for Ferruginous Hawks, whose nest areas are generally characterized by lone juniper trees or isolated patches of junipers.
This area has long been recognized as a regionally, perhaps nationally, significant area for nesting Ferruginous Hawks. Various studies of this species have been conducted in the area during the 1970?s, 80?s, and 90?s, along with monitoring by Burley and Malad BLM personnel. As of 1996, there were 46 active nests. Swainson?s Hawks, Greater Sage Grouse, and Columbian Sharp-tailed Grouse also nest in the area. Numerous other passerines, some waterfowl, and Long-billed Curlews are also present. Several small impoundments, Stone Reservoir and Sweeten Pond, attract waterfowl and other wetland-related avian species.
Some illegal shooting of birds on nests and other disturbance of nests near desert roads is a problem. On BLM lands, measures are routinely taken to protect nesting Ferruginous Hawks from disturbance via project/NEPA mitigation. In addition, BLM has assisted in annual monitoring of raptors since 1972, as well as providing artificial nest structures for raptors.
Occasional wildfires may threaten certain nest trees and habitat. Because shrub-steppe habitats and nest trees are recognized as being ecologically important, they are protected from wildfire to the extent possible. Vegetation management, treatments, and fire rehabilitation projects have also been designed to provide for structural diversity and to address prey base concerns. Other habitat concerns include the presence of Bulbous Bluegrass, which was planted as a soil conservation measure. This, along with plantings of Crested Wheatgrass, has out competed with the native species. Efforts are underway to burn, plow, or seed to remove Bulbous Bluegrass and establish desirable species.
Plant communities include: big sagebrush/native grasses; big sagebrush/ crested wheatgrass; big sagebrush/cheatgrass/ annuals; greasewood; crested wheatgrass. Less than 14? of average rain per year, but increases with altitude. The soils are from the Lake Bonneville Deposits.
There is a strong ranching and farming community influence on this area. It is a destination for upland game bird hunters, and it is a trapping site for transplanting Sharp-tailed Grouse to other historic habitats in western United States. This site has high recreational value for easily accessible, but remote, areas in southern Idaho. The Juniper Rest Stop on Interstate84 is a designated Ferruginous Hawk Watchable Wildlife Area.