Great Basin Naturalist

Volume 47 Number 2 Article 7

4-30-1987

Pygmy rabbits in the drainage

C. L. Pritchett Brigham Young University

J. A. Nilsen Brigham Young University

M. P. Coffeen Division of Wildlife Resource, Cedar City, Utah

H. D. Smith Brigham Young University

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Recommended Citation Pritchett, C. L.; Nilsen, J. A.; Coffeen, M. P.; and Smith, H. D. (1987) "Pygmy rabbits in the Colorado River drainage," Great Basin Naturalist: Vol. 47 : No. 2 , Article 7. Available at: https://scholarsarchive.byu.edu/gbn/vol47/iss2/7

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PYGMY RABBITS IN THE COLORADO RIVER DRAINAGE

C, L. Pritchett', J. A. Nilsen', M. P. Cofit'cir, and H. D. Sinitli'

Abstract —A range extension of the pygni\- rahl)it, Braclujlagus idahucnsis, into tlie Colorado River basin and a hypothesis as to its route of emigration.

The following report records the occur- voucher specimens and the comparison skulls rence of Brachylagus idahoeusis (Merriani) of the Idaho rabbits were deposited in the beyond its published range in the Bonneville mammal collection of the Life Science Mu- Basin. The southeastern record ofOccurrence seum, Brigham Young University. The rab- is 4.8 km NE Panguitch, Garfield Co. bits and their sign (burrows and pellets) were (Stephenson 1966). Holt (1975) reported "an essentially confined to tall big sagebrush, isolated population about 15 miles south of Artemisia tridcntata , stands in shallow

Fish Lake on the Parker Mountain. On 7 July washes. This is consistent with other observa- 1982 Michael Coffeen, Utah Division of tions on pygmv rabbit habitat as reported bv

Wildlife Resources, collected a pygmy rabbit Merriam (189i), Grinnell et al. (1930), Orr ca 16 km S of the Fish Lake Ranger Station in (1940), and Green and Flinders (1980). Ac- Wayne Co., T28S RIE S14, elev. 2,379 m, cording to some of the older ranchers in Loa, and on 12 September 1982 Mark Oveson, un- these "little rabbits ' have been there as long aware of Coffeen s specimen, reported seeing as they can remember and have been exten- pygmy rabbits 4.8 km W of Loa, T28S RIE S3, sively hunted along with cottontails and black- elev. 2, 183 m Wayne Co. (personal communi- tailed jackrabbits (personal communication, cation). Since then six live individuals plus 1984). two skulls have been collected from the Assuming that big sagebrush is essential for Parker Mountain region of Awapa Plateau. these mammals, there are three possible The live animals were used for preparing routes of dispersal that might have been used karyotypes and saved as voucher specimens. by the pygmy rabbit to emigrate from the

This is the first published report of pygmy Great Basin to the Awapa Plateau (Fig 1). One rabbits outside the Pleistocene Lake Bon- route would be to exit the Great Basin and neville (Columbia River) drainage. Awapa by following the valley formed by

Plateau is part of the Fremont River water- Peterson Creek, near Sigurd, Sevier Co., up shed that eventually enters the Colorado to Awapa Plateau. This is essentially the same River. Two of the specimens were females and route now used for Utah Highway 24. The two were males, but sex was not determined other two routes leave the Great Basin from on the other three. Selected mean measure- NE Iron Co. Janson s (1946) distribution map ments (in millimeters) of two females and two indicates a population of pygmy rabbits 24 km males compared with means from Brachyla- NW of Parowan, Iron Co. Individuals from gus reported bv Janson (1946) in parentheses this or nearby popidations could have emi- were as follows: Tot. L. 251, 218 (291) (278); grated east through Buckskin Valley and Dog Tail L. 20, 18 (17) (17); H.F. 66, 63 (70) (70); Valley into the Sevier River drainage SW of Ear. 52, 56 (50) (51). Means of greatest length Circleville, Piute Co. From that point the of skull (N = 8) compared with means of the most direct route would have been to follow same measurement on skulls from 23 pygmy the Sevier River down to its junction with rabbits from Dubois, Idaho, are respectivelv East Fork of the Sevier River north of Cir- 51.8 (S.E. = 0.72) to 49.8 (S.E. - 0.54). The cleville, thence east past Kingston along the

DepartTTit-nt ul ZuoIohn . Brigham Young University. Provo, Utah 84602. -Utah Division of WildUle Resources, 622 N. Main, Cedar Citv, Utah 84720

231 232 Great Basin Natufl\list Vol. 47, No. 2 ANPETE

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Fig. 1. Locations ol historic and present pygmy rabbit populations in the study area and routes of proposed emigration. lower portion of East Fork of the Sevier River Otter Creek drainage north through Grass to Otter Creek. This route would then follow Valley to the Parker Mountain Range. Once April 1987 Pritcmett et al. : Pycmy Rabbits 233 into the Sevier River drainage near Circleville found no sign of pygmy rabbits from Sigurd to an alternate route might have followed the Burrville, and no pygmy rabbits or sign were Sevier River south to Panguitch, the location observed through Emery Valley. Because of of Stephensen's (1966) pygmy population, and these observations, we feel the route from on south along the river to its junction with northeastern Iron Co. to the junction of the Red Canyon. This route would then cross East Fork of Sevier River, up to Otter Creek Paunsaugunt Plateau through Red Canyon and north through Grass Valley to Parker and Coyote Hollow into Emery Valley, just Mountain to be the most logical dispersal north of Bryce Canyon National Park. The route for this group of lagomorphs. East Fork of the Sevier River flows through We appreciate the comments and helpful

Emery Valley, a historic sagebrush commu- suggestions made by Drs. W. Z. Lidicker, J. nity, to its junction with Otter Creek. From L. Patton, and David Ribble, all from the this junction pygmy rabbits could have fol- Museum of Vertebrate Zoology, University of lowed the route previously suggested through California, Berkeley. Grass Valley to Parker Mountain. During the summer of 1986, we spent sev- Literature Cited eral days following the proposed routes look- ing for pygmy rabbits and pygmy rabbit sign. Green.J S .AND J. T. Flinders. 1980. Habitat and dietary Both their pellets (they pile their tiny, hard relation.ships of the pvgmv rabbit. J. Range Man- pellets like pack rats) and burrows (entrance age. 33: 136-142.

Grinnell. , Dixon, Linsdale 1930. Verte- shape) are distinctive. We were able to find J J AND J. M brate natural history of a section of northern CaU- pygmy rabbits or their sign from Burrville, ca fornia through the Lassen Peak Region. Univ. .8 km northwest of Parker Mountain, south California Publ. Zool. 35. 594 pp. through Grass Valley to just north of Otter Holt. R G. 1975. Ta.\onomy and distribution of cottontail

Creek Reservoir where big sagebrush ends rabbits, genus Sijlvil(i