The Carlisle Mosquito Online

Friday, March 1, 2002


Long-tailed Weasel

Name: Long-tailed Weasel (Mustela frenata)

When and where seen: Tracks were seen and measured on January 15 in the Cranberry Bog Reservation. Most local wooded areas with access to standing water will hold weasel populations.

Description: The Long-tailed Weasel is the most widespread carnivore in the western hemisphere. It occurs locally in various habitats such as forests, meadows, and wetland areas. A small, energetic predator reaching lengths of 22 inches and weighing up to 9 pounds the Long-tailed Weasel is currently displaying its white winter pelage with a black-tipped tail. During summer months, it reverts back to a chestnut brown coat with a buff/yellow underside.

Food: Active day and night, and maintaining a territory of up to 40 acres, this weasel pursues various rodent species, rabbit, ground birds, insects, worms, and makes the occasional raid on the local chicken coop, storing away excess prey in caches.

Behavior: Breeding occurs mid-summer with a litter of 4-8 kits born the following spring (due to delayed embryonic implantation common in Mustelid species). It makes dens in abandoned burrows of small mammals, often the Eastern Chipmunk (of which the Long-tailed Weasel is the chief predator), and will line the nest with the fur of its prey.

Signs: Evidence of the Long-tailed Weasel can be confirmed through snow tracking; seek out the typical 2-2 bounding pattern similarly left by larger weasels such as fisher, mink and otter. These tracks are created by the hind feet landing in the prints left by the forepaws. Long-tailed tracks often appear as feathery prints (roughly 3/4" wide, 1" long) connected by drag marks and meandering trails with facial probing marks and tunnels created while pursuing voles and mice. Trail widths up to 3" inches and strides up to 43" aid in determination. Scat appears as small, twisted deposits containing rodent hairs. Search along stonewalls or prominent objects along the trail.

References: National Audubon Society Field Guide to North American Mammals, 1996-97, Alfred A. Knopf. Tracking & the Art of Seeing by Paul Rezendes, 1999, Harper Perennial.

Ideas for species for the Biodiversity Corner are encouraged from anyone interested. The only requirements are that the species exists in the wild and was seen in Carlisle ­ animal or vegetable ­ reptile or raptor - fish, fowl or fungus ­ everything counts. This space is yours as much as mine. Send a note to Kay Fairweather at 392 School St, Carlisle MA 01741 or to

2002 The Carlisle Mosquito