Wednesday's Wildlife: Silver-Haired Bat

Under the light of the full moon, something stirs. You might catch a glimpse of silver-streaked fur slipping through the trees, or spot the flash of sharp, glinting fangs in the darkness. It slips between the trees, then vanishes before you can blink. With that eerie shimmer and those nocturnal habits, you could be forgiven for thinking it’s a creature of myth—but this creature isn’t a werewolf or a vampire. It’s a silver-haired bat.

Bats have long lived in the shadows of superstition, but these nocturnal mammals are more remarkable than ominous. They’re the only true flying mammals on Earth, using echolocation to find their prey with stunning precision. Here in Alberta, all nine of our native bat species are insectivores, consuming thousands of bugs per night, providing crucial pest control for forests, farms, and backyards alike.

Among them, the silver-haired bat (Lasionycteris noctivagans) stands out, not only for its frosted appearance but also for its migratory lifestyle. These medium-sized bats prefer dense, mature forests where they roost in tree cavities, under loose bark, or tucked beneath foliage. Unlike many other bat species, silver-haired bats are generally solitary, though females may form small nursery groups during the summer months to raise their pups.

See below for some photos of the silver-haired bat patients we've looked after at Calgary Wildlife!

While wild bats hunt insects midair, patients in care need regular hand-fed meals to stay strong.

A silver-haired bat with a tear in its patagium, the thin membrane of skin that form its wing.

Weigh-ins help wildlife rehabilitators track a bat’s health and recovery progress during care.

Warm, quiet spaces mimic natural roosting conditions, helping bats rest and reduce stress.

This overwintered patient spent 213 days in care before returning to the wild.

In Alberta, silver-haired bats arrive in spring to breed and feed, but by late summer, they begin a remarkable migration. These bats can travel over 1,600 kilometers to reach their wintering grounds in the southern United States or along the Pacific Coast (South Carolina DNR, 2015). This journey is fraught with danger, particularly from wind turbines. Migratory tree bats like the silver-haired, hoary, and eastern red bat are disproportionately affected by turbine mortality (Baerwald & Barclay, 2009). They make up more than 72% of bat deaths at wind energy facilities (American Wind and Wildlife Institute, 2018). Some are struck directly, but many suffer internal injuries caused by rapid pressure changes near spinning blades—a phenomenon known as barotrauma (Florent & Bennett, 2024).

This mortality has contributed to severe population declines. In 2023, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) designated the silver-haired bat as Endangered. Researchers estimate their numbers have dropped by over 50%, primarily due to collisions with wind turbines during migration (COSEWIC, 2023). Their reliance on forested habitats also makes them vulnerable to logging and urban development, further reducing suitable roosting sites.

With smart planning and targeted mitigation, wind energy can be both renewable and bat-friendly.

Still, there is hope. Studies show that modest changes to turbine operations, such as raising the wind speed threshold for blade rotation during peak migration periods, can significantly reduce bat fatalities without major energy losses; this is because the vast majority of fatalities occur at lower wind speeds, when bats are more likely to be flying (Sotillo et al., 2024). Other innovations, like ultrasonic deterrents and improved site planning, show promise in making wind energy more wildlife-friendly. Renewable energy and bat conservation can coexist with thoughtful design and policy.

At Calgary Wildlife, we understand the challenges these bats face and are uniquely equipped to support their recovery and care. Our specialized bat care program includes a 40-foot outdoor flight pen, allowing bats to regain strength, practice echolocation, and hunt live insects during summer rehabilitation. For those who arrive too late in the season or need extended care, we maintain a temperature- and humidity-controlled trailer affectionately known as the "bat cave." This overwintering unit includes an indoor flight space and mimics natural torpor conditions, giving bats the chance to survive until release is possible.

The white trailer on the right is Calgary Wildlife’s “Bat Cave", a temperature- and humidity-controlled unit for housing and overwintering bats. To the left, the wooden structure is our enclosed outdoor flight pen, used during summer to help bats rebuild flight muscles and practice echolocation.

Our team is led by Melanie Whalen, our Director of Wildlife Care and Services and a nationally recognized bat expert. She was part of the first team to identify white-nose syndrome (WNS) in eastern Canada and helped establish the country’s surveillance program. WNS is a devastating fungal disease that has killed millions of bats across North America, particularly those that hibernate in caves (Canadian Wildlife Health Cooperative, 2017). While silver-haired bats are migratory and less susceptible to WNS, the presence of the fungus on their bodies remains a concern (Government of BC, 2024).

We work closely with partners like Alberta Environment and Protected Areas (AEP), the Alberta Community Bat Program, and the Calgary Urban Species Response Team. These organizations help transport injured or displaced all nine species of Alberta bats to our facility, especially during migration or when they’re found in inappropriate locations. Our bat cave is the only one of its kind in Canada, so we frequently provide overwintering care for bats, including those transferred from other wildlife rehabilitation organizations like the Alberta Institute for Wildlife Conservation (AIWC), as part of the collaborative efforts among rehabbers.

Handcrafted by Calgary Wildlife, this custom bat box provides a safe summer roost for local bats. To be effective, bat boxes should be installed at least 12 feet off the ground with a clear drop below to allow for easy takeoff and landing.

The silver-haired bat may wear the look of legend, but this shimmering mystery of the night is no myth—it’s a remarkable little traveller on an epic journey. Now that you know its story, you can help ensure these extraordinary creatures continue to thrive. Here’s how you can support their survival:

• Never touch a bat with your bare hands. While the risk of rabies in bats is rare, it’s still a possibility.

• If you find one grounded or active in the winter here in Alberta, it likely needs help—call a wildlife rehabilitator.

• Consider installing bat boxes to provide safe roosting sites, especially as natural tree cover declines.

• Avoid using pesticides that reduce insect prey.

• Support bat-friendly wind energy policies and habitat conservation efforts.

These small, shimmering mammals are vital threads in our ecological fabric. By understanding their needs and advocating for their protection, we ensure that the silver-haired bat—and all bats—continue their silent flights beneath the stars.

For assistance with injured wildlife, please contact the Calgary Wildlife Rehabilitation Society at 403-214-1312.

Support A Patient

Even tiny predators need a helping hand sometimes. Watch one of our silver-haired bat patients enjoy a well-earned snack. In care, hand-fed insects help maintain energy and weight—especially for bats recovering from injury or migration stress.

References:

• American Wind Wildlife Institute. (2018). Bats and wind energy: Impacts, mitigation, and tradeoffs. https://rewi.org/wp-content/uploads/2018/12/Bat-Issue-Brief-11_15_18.pdf

• Baerwald, E. F., & Barclay, R. M. R. (2009). Patterns of bat fatalities at wind energy facilities in North America. Journal of Wildlife Management, 72(1), 61–78. https://doi.org/10.2193/2007-221

• Canadian Wildlife Health Cooperative. (2017). White-nose syndrome impacting bats in Canada – Fact sheet. https://www.cwhc-rcsf.ca/docs/WNS-FactSheet_2017_EN.pdf

• Committee on the Status of Endangered Wildlife in Canada. (2023). COSEWIC assessment and status report on the silver-haired bat (Lasionycteris noctivagans) in Canada. https://wildlife-species.canada.ca/species-risk-registry

• Florent, S. N., & Bennett, E. M. (2024). Wind turbines kill bats, but they don't have to. Austral Ecology, 49(2), e13495. https://doi.org/10.1111/aec.13495

• Government of British Columbia. (2024). White-nose syndrome in bats. https://www2.gov.bc.ca/gov/content/environment/plants-animals-ecosystems/wildlife/wildlife-conservation/wildlife-health/white-nose-syndrome-wns#aboutWNS

• Sotillo, A., Le Viol, I., Barré, K., Bas, Y., & Kerbiriou, C. (2024). Context-dependent effects of wind turbines on bats in rural landscapes. Biological Conservation, 295, 110647. https://doi.org/10.1016/j.biocon.2023.110647

• South Carolina Department of Natural Resources. (2015). Species of conservation concern – Silver-haired bat (Lasionycteris noctivagans). In South Carolina state wildlife action plan: Supplemental volume. https://www.dnr.sc.gov/swap/supplemental/bats.pdf