Ondatra zibethicus osoyoosensis (Lord)
Muskrat
D. Watson (in letter of January 16, 1957) reported that he has seen muskrat tracks many times along the Mancos River. He also relates a report received from Chief Ranger Wade and D.A. Spencer who saw a muskrat, no doubt a wanderer, on the Knife Edge Road on a cold winter night. These men, both reliable observers, stopped and saw the muskrat at a distance of two feet, where it took shelter under a power shovel parked beside the road. Reports of dens seen along the Mancos River are available for 1944, 1945, 1946, and 1947.
Microtus longicaudus mordax (Merriam)
Long-tailed Vole
Specimens examined.—Total, 36: North end Mesa Verde National Park, 7000 ft., 76233–76237; entrance to Mesa Verde National Park, 5123–5126 in Denver Museum; Prater Canyon, 7600 ft., 76238–76244; Upper Well, Prater Canyon, 7575 ft., 69441; Morfield Canyon, 7600 ft., 76245–76259, 76261–76263; west bank Mancos River, northeast side Mesa Verde National Park, 76260.
The vegetation at the above-named localities is a combination of brush and grasses that are both more luxuriant than in areas dominated by pinyon and juniper on the more southern and altitudinally lower part of the top of the Mesa where no M. longicaudus was taken.
Microtus mexicanus mogollonensis (Mearns)
Mexican Vole
Specimens examined.—Total, 22: Prater Canyon, 7600 ft., 76283–76287; Sect. 27, head of east fork of Navajo Canyon, 7900 ft., 69442; Far View Ruins, 7700 ft., 69443, 79223–79224; 2 mi. NNW Rock Springs, 7900 ft., 69444–69446; Park Well, 7450 ft., 69447–69453; rock ledge at head of Spruce Tree Canyon, unnumbered specimen in Denver Museum; Headquarters, MV 7895/507, 7896/507.
The first specimen of the Mexican vole from Colorado was obtained on the Mesa Verde and has been reported by Rodeck and Anderson (1956:436). Specimens have now been taken at seven localities on the Mesa. Prater Canyon is the only one of these localities at which any other species of vole was taken. There Microtus longicaudus and Microtus montanus were also obtained. Judging from the vegetation at the above localities, M. mexicanus is to be expected in drier areas with less cover than M. montanus inhabits, and in areas having less cover than those inhabited by M. longicaudus.
Microtus montanus fusus Hall
Montane Vole