We examined attributes of 45 roost sites used by 17 adult male evening bats (Nycticeius humeralis
) in a diverse forested landscape within the Ouachita Mountains, Arkansas. Bats roosted in a diverse array of substrates, including live or dead Pinus echinata $15 cm diam at breast height (29% of roosts) and small (,10 cm) understory or midstory hardwoods (20% of roosts). Sixty-three percent of roosts were in snags, 29% in live trees and 8% were on or near the ground. One roost was located in tree foliage, one in leaf litter and one was underground in what appeared to be a small-mammal burrow. Logistic regression models indicated that sites surrounding roosts were more likely to have fewer stumps and more hardwoods snags $10 cm diam at breast height than random sites. At the forest-stand level, all roosts were in stands with a mature (.50 y old) overstory. Twenty-six roosts (58%) were in stands that had undergone partial harvest, midstory removal and burning within the last 6 y, but 13 (50%) of those roosts were in unharvested inclusions (greenbelts) retained along stream drains within these stands; thus, 71% of all roosts were in unharvested patches of forest. Male evening bats were flexible in their roost selection, using a range of tree types (both live and dead), sizes and forest habitats. Possibly because cooler sites allow more frequent use of torpor during summer, they often roosted in small understory snags and in closed-canopy forest stands where these small snags were abundant. However, they also roosted in partially harvested portions of stands where a mature overstory was retained. Our results suggest that management intended to provide optimal roosting sites for females may not be applicable to male evening bats.
Perry, Roger W.; Thill, Ronald E. 2008. Diurnal roosts of male evening bats (Nycticeius humeralis) in diversely managed pine-hardwood forests. American Midland Naturalist. 160: 374-385.