Survey of Pygmy Rabbit Distribution, Numbers and Habitat Use in Lemhi and Custer Counties, Idaho

From April to September 1997 and July to August 1998, I conducted a survey for the Bureau of Land Management on the Salmon and Challis Field Office Areas, Idaho, to determine the current distribution, habitat associations and relative densities of pygmy rabbits (Brachylagus idahoensis). The survey area was on mostly public lands in three separate block fault valleys -- Lemhi River/Birch Creek, Pahsimeroi River/Little Lost River and Warm Springs Creek/Big Lost River, totaling approximately 583,600 acres. The survey consisted of reconnaissance from a vehicle and on foot to determine outer limits of the rabbit's occupied range and measurement of density of burrows on belt transects whenever a substantial amount of sign was found. The pygmy rabbit occupies a continuous band of sagebrush habitat from Kaufman Guard Station (on Birch Creek) northwestwards to Hayden Creek (tributary of the Lemhi River) at elevations from 5,600 to 7,300 feet; a continuous band of sagebrush habitat from Summit Creek (tributary of the Little Lost River) northwestwards to the village of May (on the Pahsimeroi River) at elevations from 5,400 to 7,700 feet; and a continuous band of sagebrush habitat from Mackay (on the Big Lost River) northwestwards to Grand View Canyon (on Warm Springs Creek) at elevations from 5,800 to 7,300 feet, except where interrupted by cultivated lands, recent range fires, sagebrush eradication and areas of unproductive soil. Its most preferred habitat was scattered low earth mounds ("Mima mounds") in Artemisia tridentata ssp. Wyomingensis habitats at elevations between 6,200 and 6,500 feet elevation where sagebrush heights were 24 to 48 inches and crown cover was 40 to 50 percent on the mounds, surrounded by expanses of 12 to 24 inch tall sagebrush and crown cover of 20 to 30 percent between the mounds. Rabbits were also found in adjacent areas but at much lower numbers.