Silver-haired Bat
A slow-flying bat that is often seen near woodland ponds and streams, they are sometimes hooked by anglers fly-fishing.
About This Species
A medium-sized bat with black hair tipped in silver or yellow; the silver-haired bat is one of Colorado's most distinctive and attractive mammals. The slow flight of this bat is unusual, and they often fly close to the ground or over water. Because silver-haired bats roost in tree hollows and behind loose bark, clear-cutting and removal of standing dead trees may affect their distribution and abundance.
Living with Bats
There are 18 species of bat that call Colorado home. These amazing mammals are not only fantastic insect control, but are also valuable pollinators. Learn more about how humans and bats can live in harmony in our guide.
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Physical Characteristics
Wingspan ranges from 270 to 310 mm. Average measurements of 10 males from northwestern Colorado were: total length, 104 mm; forearm, 39 mm; and weight, 12 g.
Range
This is a northern species that occurs throughout Alaska, Canada and all of the contiguous United States except Florida. In Colorado it is found statewide but is more common in the forested mountains at elevations to 10,000 feet.
Habitat
The silver-haired bat is usually solitary, but it is occasionally found in pairs. It roosts in trees, under bark, under rocks and infrequently in open soft-walled caves or mines. Silver-haired bats also roost in open buildings, such as sheds or garages. It is seldom found in closed structures, such as the attics of houses. This bat probably doesn't winter in Colorado but instead migrates elsewhere to spend the colder months. Field data indicate the silver-haired bat is most abundant during late spring and early fall when both sexes are found in the state. However, pockets of activity throughout the summer have been noted more recently for this species.
Diet
Like all Colorado bats, the silver-haired bat is an insect-feeder, preferring moths, flies, beetles and wasps. The silver-haired bat is a slow flyer, often seen foraging near the ground. It commonly flies around ponds and woodland streams.
Reproduction
Little is known of the reproductive habits of this species. Two young are produced in early summer. Mating probably occurs in autumn with the female storing sperm during the winter. Ovulation occurs in April or May. Gestation is 50-60 days. There is some evidence that the sexes are segregated during summer. Silver-haired bats occasionally form fairly large nursery colonies of 200 or more females and their young.
Threats to Species
Predators include skunks, owls and probably snakes.