Technical Report #85-5-03 the HERPETOLOGY of the OWYHEE
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FISH & WILDLIFE REFERENCE LIBRARY Technical Report #85-5-03 1985 THE HERPETOLOGY OF THE OWYHEE RIVER DRAINAGE, MALHEUR COUNTY, OREGON ik, A." 5w, Al Oregon Department of Fish and Wildlife Nongame Wildlife Program THE HERPETOLOGY OF THE OWYHEE RIVER DRAINAGE 14ALHEUR COUNTY, OREGON Alan D. St. John Oregon Department of Fish and Wildlife Nongame Wildlife Program Technical Report #85-5-03 1985 CONTENTS Page ABSTRACT 1 ............................................................... INTRODUCTION@ 1 .......................................................... STUDY AREA AND METHODS 2 ................................................. RESULTS 4 ................................................................ 6 Species Accounts -- Amphibians Long-toed Salamander .................................... 6 Great Basin Spadefoot......................................... 7 Western Toad ........................................ 7 Woodhouse's Toad................................................. 8 ............................................. 9 Pacific Treefrog ............................................. Spotted Frog 9 Northern Leopard.................................................Frog 10 ........................................ 10 Bullfrog ..................................................... Accounts 11 Species -- Reptiles ...................................... Desert Collared Lizard 11 Long-nosed Leopard Lizard....................................... 12 Western Fence Lizard .................................... 13 Sagebrush Lizard ........................................ 14 ............................................. 15 Side-blotched Lizard ......................................... Desert Horned Lizard 15 Short-horned Lizard ......................................... 16 Western Skink .......................................... 17 Western Whiptail................................................ 17 Rubber Boa ............................................. 18 Racer ................................................... 19 ........................................................ Striped Whipsnake 19 Gopher Snake ............................................ 20 Common .................................................Snake 21 Garter .......................................... Western Terrestrial Garter Snake 21 Ground Snake ............................. 22 Night Snake ................................................. 24 .................................................. 26 Western Rattlesnake .......................................... 27 Hypothetical Species ............................................. Striped Chorus Frog 27 Snake ......................................... 27 Long-nosed ............................................ DISCUSSION 28 ............................................................. ACKNOWLEDGEMENTS 31 ....................................................... REFERENCES 31 ............................................................. i Contents (continued) P age APPENDICES Appendix A. Bibliography of Oregon herpetology 33 ................... Appendix B. Locality data abstract for protected and uncommon species of the Owyhee River Drainage, Malheur County, Oregon ....................................... 34 Appendix C. Distribution maps for the herpetofauna of the Owyhee River drainage, Malheur County, Oregon 43 ........ THE HERPETOLOGY OF THE OWYHEE RIVER DRAINAGE, MALHEUR COUNTY, OREGON Alan D. St. John ABSTRACT A herpetological inventory of the Owyhee River drainage, Malheur County, Oregon, was conducted in 1984 and 1985, with emphasis on the status and distribution of the ground sna-keV .. IdFINUId6d)-X and- other rare or kaullurd 1 uncommon species. 7`xc essive y dry e ather conditions probably affected inventory results, particularly for amphibians. However, 17 of the 23 species of amphibians and reptiles reported for the lower Owyhee River drainage were found in 1984; 14 of 19 species were found along the upper Owyhee River drainage in 1985. Distribution records are summarized and mapped for all species located, along with historical records. The ground snake was found at only two locations along the lower Owyhee drainage, but probably occurs throughout the study area. Woodhouse's toad (Bufo woodhousei) and the northern leopard frog (Lana pipiens) are apparently restricted to the lower Owyhee drainage. With the exception of the short-horned lizard (Phrynosoma douglassi) and the desert horned lizard Rhrynosgma@r 5nos), the large Great Basin lizards R foun in good numbers in the Owyhee River drainage. These populations should remain secure in this remote, southeast corner of Oregon, although the invasion of introduced grasses may impact the habitat of some species. INTRODUCTION The herpetofauna of the Owyhee River drainage in southeastern Oregon has never been thoroughly studied. This is particularly the case with the upper section of the river above Rome, Malheur County, Oregon. As far as I know, no prior studies had ever been made of the remote canyon country, generally known as the "Three Forks Area." Because the main canyon of the Owyhee is in the relatively lower and warmer upper sonoran life zone, the area supports a good variety of herpto- fauna. However, due to the arid climate (precipitation varies from 8 to 13 inches), more reptile species are to be found there than amphibian. Seven species of amphibians are native to the Owyhee area, with an eighth, the bullfrog (Rana catesbeiana) being an introduced species; 16 species of reptiles have been recorded. However, four of these species have yet to be -1- recorded from the upper stretches of the river. These are Woodhouse's toad (Sufo woodhousei), (Rana northern leopard frog pipiens , short-horned lizard (Phrynosoma douglassi), and the ground snake (Sonora semiannulata). In many places, watercourses have cut through the basalt formations and eroded into the softer sedimentary layers below, creating sandstone "bad- lands." in these areas, a sandy soil with typical arid-lands plants (e.g., greasewood, hopsage, and shadscale) present the correct habitat for many typically Great Basin reptiles from the south to occur. There is also a faunal influence made by the Owyhee River's connection with the drainage system of the Snake River. This has allowed several species to penetrate from southwestern Idaho. A herpetological inventory of the Owyhee River drainage was conducted in 1984 and 1985 through the Nongame Wildlife Program of the Oregon Department of Fish and Wildlife as part of a statewide effort to determine the distribution and status of Oregon's amphibians and reptiles. STUDY AREA AND METHODS From 4 June to 15 July 1984, I conducted a herpetological inventory of the lower Owyhee River drainage. The study area was designated as that portion north of the backwaters of the Owyhee Reservoir to the confluence with the Snake River. The upper Owyhee drainage, designated as that portion south of the backwaters of the Owyhee Reservoir to where the river enters Oregon at the Idaho border, was inventoried from 3 June to 26 July 1985 (Figure 1). My field methods involved locating a promising looking hillside, canyon, flat, or stream, and then systematically "working" the entire area. For example, if the habitat was a rocky hillside, I would slowly "zig-zag" up the slope, searching the tops of rocks for sunning lizards and snakes, along with looking under rocks and other surface debris for the secretive varieties. Essentially the same method was used on sandy flats, weaving back and forth between the bushes to investigate lizard populations. Although usually working by myself, through this tight switchbacking I can generally investigate an area quite thoroughly. -2- 356 7 d W. Plymouth a At A L H E U t U40, '3 DM Lah, i J,MIN Va. Flats ft.j mm. W N t t t t 15 cited. -- 57H OREGON Figure 1. Owyhee River drainage, Malheur County, Oregon. -3- The edges of ponds streams, and rivers were searched for aquatic species such as frogs, toads, and their larvae. Lizard inventorying was primarily done in the cooler morning hours from 0800 to 1100 hours, as the mid-day temperatures were usually too high for most species. From approximately 1900 to 2400 hours, I would slowly drive along roads looking for crossing snakes. On several niahts I searched alone the edges of the river or ponds for nocturnal frogs and toads. Although observational data was recorded for all species encountered, special attention was placed on the ground snake. These little snakes are known from only four or five locations in southeastern Oregon, all in the lower Owyhee River drainage. Because of their secretive habits, little is known of their distribution and life history in Oregon. Other uncommon species or those of limited distribution were emphasized including Woodhouse's toad, northern leopard frog, desert collared lizard (Crotaphytus bicinctores), long-nosed leopard lizard (Gambelia wislizenii), short-horned lizard, desert horned lizard (Phrynosoma platyrhinos), western whiptail (Cnemidophorus tigris), night snake (Hypsiglena torquata), and striped whipsnake (Masticophis taeniatus). Additionally, two hypothetical species that may occur in the Owyhee area were searched for. These are the striped chorus frog (Pseudacris triseriata) and the long-nosed snake (Rhinocheilus lecontei). In 1985, Dr. Robert Stebbins' newly revised edition of his "Field Guide to Western Reptiles and Amphibians" was published. Stebbins chose not to recognize some recent taxonomic revisions, and changed some common names to ones that he felt were