Lasionycteris noctivagans

Habitat is primarily forested (frequently coniferous) areas adjacent to lakes, ponds, or streams, including areas that have been altered by humans. During migration, these bats sometimes occur in xeric areas. Summer roosts and nursery sites are in coniferous or deciduous tree foliage, cavities, or under loose bark, sometimes in buildings. In the Pacific Northwest and Black Hills (South Dakota), these bats show an affinity for forests that contain large numbers of snags (Campbell et al. 1996, Mattson et al. 1996, Betts 1998). In winter, individuals have been found in mines, caves, houses, rock crevices, under loose bark, and in hollow trees.

In Oregon, maternity roosts were in cavities high in tall, declining or newly dead trees; roost fidelity of reproductive females varied among individuals: some bats used only 1 or 2 roosts from 8 to at least 13 days; others used 5 or 6 roosts from 1 to 6 days; radio-tagged bats that were in the same colony stayed together during shifts among roosts; bats moved 35 to 1,100 meters between successive roosts (Betts 1998). In South Dakota, maternity aggregations primarily were in woodpecker-created cavities in ponderosa pines (Mattson et al. 1996).

At Long Point, Ontario, late summer/early fall migrants rats roosted in a variety of tree species and human-made structures in natural and developed (e.g., residential) areas (McGuire et al. 2012). In Manitoba, migrants roosted typically in narrow crevices in tree trunks (Barclay et al. 1988).

In the Ouachita Mountains, Arkansas, Perry et al. (2010) radio-tracked 11 bats to 31 day-roosts during winter. Ninety percent of roosts were in trees (5 species): 55 percent of all all roosts were under loose bark of the bole of live overstory Pinus echinata (shortleaf pine), three percent of roosts were in a rock outcrop, and six percent were at ground level (under a tree root or in a cavity at the base of a live pine). Bats selected pine or pine-hardwood stands greater than 50 years old and used forest stands 15-50 years of age less than their availability. Most roosts were on southern topographic aspects, and bats roosted in the rock outcrop on colder days (<5 °C).

See Vonhof and Barclay (1996) for information on characteristics of roost trees in British Columbia. See Campbell et al. (1996) for roost characteristics in Washington.

During migration and summer residency, females roost alone or in maternity colonies; males typically roost alone (Barclay et al. 1988, Mattson et al. 1996, Betts 1998).

Copulation occurs in late summer or early fall. Fertilization is delayed until spring. Gestation lasts 50-60 days. Litter of 2 (occasionally 1) young is born in June-July, sometimes later in north (Kunz 1982). Young are able to fly at about 3 weeks. Individuals of both sexes become sexually mature by late summer/early fall of their first year (Cryan et al. 2012). Lifespan appears to be relatively short (oldest individuals estimated to be 12 years old; Schowalter et al. 1978). Maternity colonies are small (Parsons et al. 1986), usually with fewer than 20 individuals but sometimes as many as 55 (in a tree in South Dakota; Mattson et al. 1996).