Silver-haired Bat
Last Update/Review: June 17, 2002
The
silver-haired bat (Lasionycteris noctivagans) is a noncolonial
woodland bat which is rarely found in buildings. Though widely distributed
in North America, it is most abundant in the northern Rockies. Males
and females appear to use separate ranges during the summer but apparently
winter together in the southern United States. Silver-haired bats are
distinguished by their size — they have a wingspan up to 30 cm
(12 in); color — black wing membranes and dark silver-tipped
hair; and flight — slow and leisurely, often close to the ground.
They are strong fliers and some migrate seasonally from Arizona to
northern Alberta. Silver-haired bats use tree roosts during the summer.
They may be found as individuals or in small groups under bark, in
abandoned bird's nests, in hollow trees, or hanging upside down amongst
the leaves throughout the forests in central Alberta. During the winter,
they do not stay in Alberta but rather hibernate under the bark of
trees, in rock crevices, and occasionally, in buildings in the southwestern
United States.
Owing to their solitary nature and avoidance of humans, little is known about silver-haired bats in Alberta. They appear to be present in southern Alberta only during the spring and fall migrations (April to July, August to October, respectively). Males do not appear to migrate and, thus, records in Alberta include only adult females during the spring, and females and juveniles during the fall. Litter size is two young per female. During migration, the bats often use temporary daily roosts in open sheds and garages or on piles of lumber, railroad ties, or fence posts. The bats are most conspicuous at this time. The specific location of the summer and winter roosts is unknown.
