ADDITIONAL DISTRIBUTION RECORDS AND ABUNDANCE OF THREE SPECIES OF SNAKES IN SOUTHWESTERN IDAHO Lowell V. Diller' and Richard L. Wallace' Abstract.— New county records are reported for Hypsiglena torquata and Rhinochcihts lecontci, and additional distribution records are presented for Sonora semiannulata in southwestern Idaho. These three species are more abundant than indicated by previous records. The specific distribution of some of the more secretive snakes in Idaho is poorly known. Erwin (1925) made the first reported collections of the western grovmd snake, So-nora semiannulata, and the night snake, Hyp-siglena torquata, in Idaho. Later, Tanner (1941) and Slater (1941) each accumulated information on the distribution of amphibians and reptiles in Idaho. Tanner recorded the only known locality of the longnose snake, Rhinocheihis lecontei, from Elmore County and listed three localities each for the west-ern ground snake and night snake. Tanner also noted that a specimen of the ground snake was reportedly collected along the Snake River south of Caldwell, Canyon County. Slater (1941) listed the longnose snake only from Elmore County, the grovmd snake only from Ada County, and the night snake from Canyon and Ada Counties. Me-dica (1975) recorded the longnose snake from Elmore County and Pendlebury (1976) re-ported one new record of this snake from Owyhee County. Linder and Fichter (1977) reported five locality records of the longnose snake (Elmore and Owyhee Counties), four localities of the ground snake (Ada, Owyhee, Elmore, and Canyon Counties), and four county records for the night snake (Ada, Ban-nock, Blaine, and Canyon Counties). Six new records of the western ground snake were published recently by Ralston and Clark (1978). In the following paper, we add fur-ther to the knowledge of the distribution and abundance of these three snakes in Idaho. Methods and Materials The senior author participated in an in-tensive study of the reptiles of the Birds of Prey Natural Area (BPNA) along the Snake River in southwestern Idaho, from 1975 to 1979. During the early part of this study, he captured snakes by hand while driving roads, walking transects, and turning rocks and debris. Drift fences were also used during the last four summers of this study. Each drift fence consisted of a 30 m section of galva-nized metal 51 cm high with two "snake traps" located 7.6 m from each end. The "snake traps" were boxes 1.2 m long, 0.6 m wide, and 0.3 m high constructed out of 2.3 mm (Vs in) hardware cloth. Funnels lead into the trap from each end. A total of 40 drift fences were operated over a four-year span from 1977 to 1980. The drift fences were placed in a variety of habitats and kept in operation from early May through at least the end of July. In addition, snakes were brought to us by various other members of the BPNA research staff. Results and Discussion We collected 14 desert night snakes, H. t. deserticola, from Owyhee, Elmore, and Gem Counties in southwestern Idaho (Fig. 1), new county records for this species. The four lo-calities in Owyhee County are 2.5 mi SSW of Swan Falls, 3 mi E of Oreana, 4 mi NNE of Murphy, and 6 mi S of Swan Falls. The three 'Department of Biological Sciences, University of Idaho, Moscow, Idaho 83843. 154
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