Montana Field Guide

This house cat-sized animal is distinctly weasel-like in appearance. Has short legs, prominent ears, pointed face, and a well-furred tail constituting one-third of its total length. Stiff glossy guard hairs with dense silky under-fur. The soft, dense, yellowish-brown fur shades to dark brown on its bushy tail and legs. Pale buff to orange patch on throat and breast. Has ability to rotate hind limbs to enable descending trees headfirst. Total length: 21 to 26 inches. Weight: 1.5 to 2.75 pounds.

Mink - has white patch on chin. fisher - larger, dark brown, grizzled head and back. red fox - white tip on tail.

Non-migratory.

Primarily a boreal animal preferring mature conifer or mixed wood forests. Severe forest disturbance can significantly reduce habitat value. Uses deadfall and snags as den sites (FWP). In glacier NP most often located in mesic spruce & subalpine fir types. Stands averaged 35% canopy cover. Martens often traveled along forest cover/open area ecotones. Maternity dens in rock outcrops, tree cavities (Burnett 1981, O'Neill 1980).

Eats a variety of animal and plant materials associated with the mature forest. Is an opportunistic feeder that primarily feeds on a variety of small mammals (FWP). Meadow voles and red-backed voles were staples in Glacier NP. Also used Cricetidae, jumping mice, shrews, and ground squirrels. Use of birds, insects, and fruit variable by season. Will use snowshoe hares. (O'Neill 1980).

Pop's fluctuate in response to prey avail., juvenile dis- persal, & mortality of adult females. Ave. home range for adult male = 2.9 sq km, female = 0.7 sq km, resident juveniles = 0.7 sq km. (Burnett 1981).

Mates during summer with young born during April. Exhibits delayed implantation and an eight- to nine-month gestation. Average litter size is two to four (FWP). Breeds in Jul & Aug. Implantation occured Feb 22 & Apr 10. Parturition 25-28 days after implantation. Delayed implantation period of 8 months. Gestation of 9 months.