They have a slight upturn to their snout. The ears are 5-9 millimeters and rounded at the tops. The wing and uropatagium membranes are dark brown to black. Their fur covers almost all of these bats except for the wings, snout, ears and posterior portion of the uropatagium membrane, which is a membrane that goes between the bats legs that attaches at the ankle. The common name for silver-haired bats is derived from the silver or white tips of the black fur that covers both ventral and dorsal sides of the animal. ( Arroyo-Cabrales, et al., 2008 Kunz, 1982 Patriquin and Barclay, 2003 Perry, et al., 2010) Winter finds tend to be anecdotal, as they don't seem to hibernate in large groups. Uncommonly, they use human structures (garages, sheds, etc.) but roosting here tends to be solitary.ĭuring the winter, these bats have been found in caves and other rocky area that provide shelter, in tree cavities, and in buildings. These cavities are the locations of maternity colonies, as well as summer locations for bachelor males. They can also be found in dead trees, also called snags, that have loose bark to provide cover, and cavities in these trees. These species may be most suitable regarding the structure of the bark and cavities they provide (Kunz 1982a). Summer day roosts are typically under loose bark in trees, willows ( Salix), maple ( Acer), and ash ( Fraxinus) trees. Silver-haired bats are most commonly found in boreal or coniferous and deciduous forest near bodies of water, such as rivers, lakes, streams, estuaries or ponds. The only time the sexes are commingled is during migration and hibernation. Females have been noted to be absent in mountainous habitats in the western U.S. Populations in British Columbia may not migrate, as equal sex ratios are noted throughout the year. Western populations appear to leave hibernacula and migrate eastward and northward, while eastern populations only move northward. It appears that females will consistently migrate greater distances from hibernacula and spend the summer further northward than males. Occasionally, these bats have been documented in Bermuda.ĭuring the summer months, some populations are sexually segregated, and it appears that distance and direction of migration differs among western and eastern populations. They inhabit areas as far north as the entire lower third of Canada, with a northward peninsular extension following the coast into the lower south-central part of Alaska. The species is found as far south as the Victoria province of Mexico. Silver-haired bats ( Lasionycteris noctivagans) are found in most of the United States, with the exception of the southeast and southwestern coasts of the United States.
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