August 02, 2015 Hualapai Mexican Vole Conservation Status Review PREPARED BY Amanda Aurora, C.W.B . Eleanor Gladding Regional Scientist / Project Manager Senior Biologist/Project Manager SWCA Environmental Consultants - Austin SWCA Environmental Consultants - Tucson 4407 Monterey Oaks Boulevard, Building 1, Suite 110 343 West Franklin Street Austin, Texas 78749 Tucson, Arizona 85701
[email protected] [email protected] Introduction The Hualapai Mexican vole or Hualapai vole ( Microtus mexicanus hualpaiensis ) is a cinnamon-brown, small mammal in the Cricetidae Family. In January of 1987, the U.S. Fish and Wildlife Service (USFWS) proposed to list the Hualapai Mexican vole as endangered under the Endangered Species Act (ESA) and published the final listing rule in October 1987 (USFWS 1987a; USFWS 1987b). At that time, the species was considered “extremely rare and has among the most restricted habitats of any North American mammal” (USFWS 1987b). The USFWS in the final listing rule identified up to 14 locations in the Hualapai Mountains of west-central Arizona where the Hualapai Mexican vole (or its sign) had been observed (USFWS 1987b) (Figure 1). The USFWS also noted that “from 1923 to the present, only 15 specimens are known to have been captured in the Hualapai Mountains” (USFWS 1987b). This subspecies was differentiated by morphological characteristics from the other subspecies of Microtus mexicanus that occur in Arizona, including M. mexicanus mogollonensis and M. mexicanus navaho . The primary morphological differences differentiating the Hualapai Mexican vole from the other subspecies include: slightly longer body, longer tail, and longer and broader skull (compared to M. mexicanus navaho ) and a longer body, shorter tail, and a longer and narrower skull (compared to M.