Great Basin Naturalist

Volume 41 Number 1 Article 8

3-31-1981

Additional distribution records and abundance of three of in southwestern Idaho

Lowell V. Diller University of Idaho, Moscow, Idaho

Richard L. Wallace University of Idaho, Moscow, Idaho

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Recommended Citation Diller, Lowell V. and Wallace, Richard L. (1981) "Additional distribution records and abundance of three species of snakes in southwestern Idaho," Great Basin Naturalist: Vol. 41 : No. 1 , Article 8. Available at: https://scholarsarchive.byu.edu/gbn/vol41/iss1/8

This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. 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 semiannulata in southwestern Idaho. These three species are more abundant than indicated by previous records.

The specific distribution of some of the Methods and Materials more secretive snakes in Idaho is poorly known. Erwin (1925) made the first reported The senior author participated in an in- collections of the western grovmd , So- tensive study of the of the Birds of nora semiannulata, and the night snake, Hyp- Prey Natural Area (BPNA) along the Snake siglena torquata, in Idaho. Later, Tanner River in southwestern Idaho, from 1975 to (1941) and Slater (1941) each accumulated 1979. During the early part of this study, he information on the distribution of amphibians captured snakes by hand while driving roads, and reptiles in Idaho. Tanner recorded the walking transects, and turning rocks and only known locality of the longnose snake, debris. Drift fences were also used during the Rhinocheihis lecontei, from Elmore County last four summers of this study. Each drift and listed three localities each for the west- fence consisted of a 30 m section of galva- ern ground snake and night snake. Tanner nized metal 51 cm high with two "snake also noted that a specimen of the ground traps" located 7.6 m from each end. The snake was reportedly collected along the "snake traps" were boxes 1.2 m long, 0.6 m Snake River south of Caldwell, Canyon wide, and 0.3 m high constructed out of 2.3 County. Slater (1941) listed the longnose mm (Vs in) hardware cloth. Funnels lead into snake only from Elmore County, the grovmd the trap from each end. A total of 40 drift snake only from Ada County, and the night fences were operated over a four-year span snake from Canyon and Ada Counties. Me- from 1977 to 1980. The drift fences were dica (1975) recorded the longnose snake from placed in a variety of habitats and kept in Elmore County and Pendlebury (1976) re- operation from early May through at least ported one new record of this snake from the end of July. In addition, snakes were Owyhee County. Linder and Fichter (1977) brought to us by various other members of reported five locality records of the longnose the BPNA research staff. snake (Elmore and Owyhee Counties), four localities of the ground snake (Ada, Owyhee, Results and Discussion Elmore, and Canyon Counties), and four county records for the night snake (Ada, Ban- We collected 14 desert night snakes, H. t. nock, Blaine, and Canyon Counties). Six new deserticola, from Owyhee, Elmore, and Gem records of the western ground snake were Counties in southwestern Idaho (Fig. 1), new published recently by Ralston and Clark county records for this species. The four lo- (1978). In the following paper, we add fur- calities in Owyhee County are 2.5 mi SSW of ther to the knowledge of the distribution and Swan Falls, 3 mi E of Oreana, 4 mi NNE of abundance of these three snakes in Idaho. Murphy, and 6 mi S of Swan Falls. The three

'Department of Biological Sciences, University of Idaho, Moscow, Idaho 83843.

154 March 1981 DiLLER AND Wallace: Idaho Snakes 155 localities in Elmore County are 2 mi SE of Owyhee Counties (Fig. 3). Although none of Black Butte, 5 mi NE of Grandview, and 6 these collections represent new county re- mi NE of Grandview. The site in Gem Coirn- cords, we have more than doubled the num- ber of localities from which these species had ty is 1.5 mi E of Emmett. Hypsiglena t. deserticola were also collected from 11 sites been previously reported in Idaho (Ralston (45 individuals) in Ada County and one site and Clark 1978). S. s. isozona were collected (one individual) in Canyon County. from one site in Canyon County, 10 sites in Nine western longnose snakes {Rhino- Ada County, 5 sites in Elmore Coimty, and 6 cheilus lecontei lecontei) were taken from sites in Owyhee County. four localities in Ada County and one speci- Desert night snakes were collected in a va- men was collected in Canyon County (Fig. riety of habitats, including rocky areas along the canyon rim of the Snake River, at the 2). These are new county records for this spe- in cies. The localities in Ada County are 1 mi base of talus slopes, and shadescale [Atri- SE of Swan Falls, 2 mi S of Swan Falls, 3.5 plex confertifolia) and greasewood {Sarco- the mi SSE of Swan Falls, and 1 mi NW of Swan batus vermiculatus) areas away from Falls. The one site in Canyon County is 5 mi Snake River canyon. Western longnose snakes were collected in almost all major S of Melba. We also collected four R. I. le- contei from three additional localities in habitats in southwestern Idaho. This included Owyhee County. Three additional specimens areas adjacent to various agricultural lands, were collected by Roger Whitney during the rocky and sandy areas, open desert lands, and summer of 1971 around residences at the riparian habitats. Western ground snakes ap- Marsing Job Corps Center. pear to have the most restricted habitat re- We collected 35 Great Basin ground quirements of these three snake species. With snakes {Sonora semiannulata isozona) from only a few exceptions, all ground snakes were 22 localities in Canyon, Ada, Elmore, and collected in or near talus or scree slopes. The

IM E V A O A

Fig. 1. Distribution of Hypsiglena torqiiata deserticola in Idaho. Some new localities are not shown because of close proximity to other localities. 156 Great Basin Naturalist Vol. 41, No. 1 snakes that were not actually in loose rocky of the new county records are housed in the slopes appeared to be utilizing small burrows collection at the University of Idaho. probably formed by some in compact loess near the base of these rocky Acknowledgments slopes. The paucity of records for these three We thank Graham Smith and other mem- snake species would indicate that they are all bers of the Snake River Birds of Prey re- rare in Idaho. However, as indicated by search staff for collecting some of our speci- Linder and Fichter (1977), they are all secre- mens. Ted Daehnke worked as a field tive, fossorial, or noctvimal snakes that are assistant on this study and collected many of not easily collected and may be more abun- the snakes. Roger Whitney provided informa- dant than the records indicate. Our total col- tion on longnose snakes from Marsing. We lection of 60 night snakes, 46 longnose especially thank Mike Kochert, project lead- snakes, and 36 ground snakes confirms that er of the Snake River Birds of Prey research these snakes are not very rare in southwest imit, and the Bureau of Land Management Idaho and that they can be collected in ap- for funds that made this work possible. preciable numbers by employing the proper techniques. Of the three species, our records suggest that night snakes are the most abun- Literature Cited dant, followed by longnose snakes, and then ground snakes. Ground snakes seem quite Erwin, R. p. 1925. Snakes in Idaho. Copeia, 1925 No. abundant in the areas where they occur, but 139:6-7. Linder, A. D., and E. Fichter. 1977. The amphibians their more restricted habitat makes their and reptiles of Idaho. Idaho State University overall abundance low. Press, Pocatello. 78 pp. Many of the specimens we collected were Medica, p. a. 1975. Rhinocheilus. Cat. Amer. Amph. & marked and released for future studies. Most Kept. 175.1-175.4.

CANYOIM

A««

OWYHEE

N E V A A

Fig. 2. Distribution of Rhinocheilus lecontei lecontei in Idaho. Some new localities are not shown because of close proximity to other localities. March 1981 DiLLER AND WALLACE : IdAHO SnAKES 157

V A D A

Fig. 3. Distribution of Sonora semiannulata /.voronr; in Idaho. Some new localities are not shown because of close proximity to other localities.

Slater, R. 1941. The distribution of amphibians and Pendlebury, G. B. 1976. Second occurrence of the long- J. Pap. Biol., College of Pa- nose snake, Rhinocheilus lecontei lecontei, in reptiles in Idaho. Occ. 14:78-109. Idaho. Great Basin Nat. .36(1 ):56. get Sound. No. 1941. The reptiles and amphibians of Ralston, G. L., and W. H. Clark. 1978. Additional re- Tanner, W. W. 2:87-97. cords of the western ground snake, Sonora semi- Idaho. No. 1. Great Basin Nat. for Idaho. Sci. annulata, J. Idaho Acad. 14(2):35-38.