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.
Bat Conservation
Bats remain one of the most mysterious land mammals, especially in Colorado, where 18 species spend at least part of the year. For example, the little brown bats in our state seem to hibernate differently than those on the east coast, and we are constantly learning about their whereabouts, habitats and behaviors. Our current research suggests that bat populations in Colorado are doing quite well.
One little brown bat can eat up to 18,000 small insects (like mosquitoes) each night. Their economic impact is estimated to be billions of dollars, and much of the agricultural industry relies on their insect control.
Beyond their economic impact, bats flaunt some impressive adaptations. They are the only mammal that truly flies, which requires a very unique anatomy. Their upside-down lifestyle requires adaptations in their “feet” to consistently grip. If people hanged upside down for even an hour, we’d lose consciousness; bats have developed amazing blood pressure accommodations to fit the lifestyle.
We are currently involved in a monitoring partnership called the North American Bat Monitoring Program (NA Bat). The program utilizes acoustic surveys to collect information on bat populations without interfering with their behaviors. We also are using PIT tags, like the chips put in household pets, to monitor a number of maternity sites. While data collection will take years, we’ve already learned new information about Colorado’s bat population, the most heartening of which is that the population appears larger and more widespread than we’d thought. This is an excellent start to learning more about the species, but we’ve got lots of problem-solving and technological innovation left to do.
Our priorities also include learning more about bats so that we are prepared for the potential spread of White-nose Syndrome. Finding and monitoring bats is crucial to this effort, but also comes with its own challenges. Because bats are small, flying mammals, much of the equipment used to track other species is too heavy for them. And during the winter, Colorado bats are very elusive, choosing to hibernate in small groups often in locations that are inaccessible to people.
More Information:
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.