USE OF THE FOREST CANOPY BY BATS

Of the 15 species of bats in the Pacific Northwest, 11 are known to ma ke regular use of the forest canopy for roosting, foraging, and reprod uction. This paper reviews roosting requirements, foraging, and the im portance of landscape-scale factors to canopy-using species in the Nor thwest. Many northwest bats use several different types of free roosts . Common roosting sites are in cavities, crevices, and foliage. Factor s that may be important in roost site selection include microclimate, roost structure, crown architecture, canopy tree age and species, bark characteristics, foliage density, and stand and landscape composition . Some representative Pacific Northwest cavity- and crevice/bark-roost ing species include the little brown bar (Myotis lucifugus), silver-ha ired bat (Lasionycteris noctivagans), and long-legged bar (M. volans). Only two Pacific Northwest species are known to roost in folia e. Sev eral species forage in forest gaps, along forest edges, or in riparian areas. Long-eared (M. evotis) and Keen's (M. keenii) bats may forage within the forest canopy, although foraging behavior of these species in the Pacific Northwest is not well documented. Stand- and landscape- scale complexity may be important in providing bats with the abundance and diversity of roost, foraging, and hibernation sites they require.