Description: This medium-sized bat is distinguished from other Kansas bats by: 1) dark blackish-brown hairs frosted with silver (from which it gets its name), 2) hair covering the entire dorsal surface, and the front half of the underside of the tail membrane, and extending to elbows on the wings, 3) wing membranes black to brown, and 4) ears and tragus broad and round, the tragus being only half the length of the ear. Sexes are alike and show no seasonal pelage change.
Size: Adults may attain the following dimensions: total length 91-108 mm; tail 38-45 mm; hind foot 7-10 mm; ear 12-18 mm; weight 8.5-12.5 grams.
Range and Habitat: Silver-haired bats are migratory, passing south across the state in the autumn to overwinter in warmer climates. In spring it moves to its summer range north of Kansas. There are a few records, however, of Silver-haired bats hibernating in the northern part of the range. Most records are from western Kansas, although it is believed that this species may migrate across the entire state. It rarely inhabits caves, but is most abundant in deciduous forests and along their edges, especially near water courses. In forests it roosts in hollow trees or under bark, but also uses buildings on occasion.
Reproduction: Mating occurs in late August or early September. Sperm remain in the uterus during the winter and fertilize the eggs that are released in spring from the ovary. Two black and wrinkled young are born in June or early July. Only one litter is produced each year. The young remain in the tree roost while the female forages. They nurse for four to five weeks.
Habits: Silver-haired bats appear to be rare mainly because they are solitary for much of the year and roost in trees where they are difficult to find, in contrast to colonial bats which form large colonies whose location is often conspicuous. The flight of this bat is often slow and leisurely, and appears less erratic than that of myotis. Long distance migrations are undertaken at night.
Food: In Kansas this species begins feeding early in the evening, and prefers openings among trees (especially areas bordering forests) and open fields where it searches for nocturnal insects. Sometimes an audible chirping call of this bat can be heard. Foraging activity exhibits two peaks, with a lull around midnight. The first peak occurs two to four hours after sunset, and the second, two to six hours later.
Remarks: Owls are the principal predators when these bats are foraging, but skunks have been reported to eat them also.