Silver-haired bat

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The Silver-haired bat is a medium-size bat. Nearly black, with silvery-tipped hairs on back, giving frosted appearance. Lightly furred above an interfemoral membrane . Short, rounded, naked ears. Generally regarded as a solitary, tree-roosting species, it emerges in early evening, flying very slowly to feed on a variety of insects, especially moths, caddis flies, and flies.

Length: 3⅝–4¼" (92–108 mm); Tail: 1½–1¾ 3/4" (37–45 mm); HF: ⅜" (9–10 mm); FA: 1½–1¾" (37–44 mm); Weight: ¼–½ oz (9–15 g).

[edit] Breeding

Mates in fall though implantation is delayed until spring. Usually 2 young are born in early summer, generally in hollows or crevices in trees. Although this is thought to be a solitary bat, females apparently may form maternity colonies.

[edit] Habitat

Both deciduous and coniferous forests. In summer, it roosts in protected spots such as under bark or in dead trees, woodpecker holes, or bird nests. In winter, hibernates in trees, crevices, buildings, and other protected places. There are a few records of it roosting among foliage.

[edit] Range

Across southern half of Canada and southward through most of U.S. In summer, found in much of Western U.S., but in East only in Northern U.S. and Canada.

Generally migrating south for the winter, it possesses a well-developed homing instinct; one bat traveled 107 miles (172 km) to its home roost. Over major parts of its range it is present only during the spring and fall migrations. In winter, it hibernates from the latitude of middle Indiana and southward. In southern Illinois, it occasionally hibernates in silica mines but rarely enters caves. Some Silver-haired bats not only over-winter as far north as Washington state, but will become active and forage on rainless evenings following warm winter days (daytime temperature greater than approx. 50 degrees F.). Foraging during the winter months of November 2005 through February 2006 were documented in Olympia, Washington.