Fewer bats will be flying across the evening sky in the coming months. This is the time of year when some species go into hibernation, winter comfortably in narrow rock crevices or caves.

Fortunately, this disappearance is only seasonal. Bats are essential to the functioning of healthy ecosystems. They are help cycle nutrients in the environment and pollinate plants. They are too they eat agricultural pestswhich reduces the need for pesticides.

Bats are a huge asset to our ecosystems, but because they do their work under the cover of darkness, we don’t always realize how much help they provide.

Habitats under threat

Even more alarming than this seasonal disappearance is that bat populations have increased has been declining in North America for decades. Habitat loss due to forestry, urbanization and conversion of land into agricultural land reduces suitable habitat for bats, while pesticide use kills the insects they feed on.

These effects are exacerbated by the fungus Pseudogymnoascus destructans, which causes white nose syndrome. This fatal fungus is responsible for the death of more than six million bats in North America.

White-nose syndrome has been particularly devastating in Eastern Canada, where it originated the population has declined by more than 90%. small brown myotis (Myotis lucifugus) and northern myotis (Myotis septentrionalis).

The mushroom makes its way further to the west, from v first reported case in Saskatchewan in July. White-nose syndrome has yet to be identified in British Columbia, but the deadly threat is looming.

Our research group at the node BC st Canadian Wildlife Conservation Co-operative has been working to maintain wildlife health for over ten years. To understand the threats it now faces 15 species of bats that live in British Columbiawe studied 275 bats that died between 2015 and 2020. We found that the most common causes of death were related to human activities

This information can help us track bat populations over time and in response to urbanization and climate change. To help bats live, we need to know why they die.

Killer cats

A quarter of the bats in our study were killed by cats. It was not surprising – domestic cats known predators of wildlife. It is estimated that 390 million animals are killed annually by stray cats in Australia.

Read more: Don’t let them out: 15 ways to keep your pet cat happy

Free cats put not only a risk to bats, but also to biodiversity. Some cities in Iceland have introduced a curfew save the dwindling bird population.

One of the most surprising discoveries was that most of the cat-killed bats we found were female and in relatively good condition. Such a large proportion of dead female bats may be due to cats go out in the maternity ward where female bats give birth and raise their young.

Because bats have relatively several young each yearthe loss of female bats in good condition has extreme consequences for their future population numbers.

The easiest solution here is to keep domestic cats indoors and control the time the cat is outside. Cats only bring 20 percent of their winnings go hometherefore, owners are likely to be unaware of the extent of their feline friends’ hunting habits.

Recent studies show that these actions are most important near woodlands. It has been found that cats are more likely to hunt wildlife closer than 500 meters from forests than further away. One way to minimize the risk to wildlife may be to focus on managing cats that live near woodlands.

Keeping cats indoors also benefits cats: house cats live longer than cats living outside.

Worlds collide

Half of the bats in our study died from human-related causes. This is partly because the bats we studied were introduced to our laboratory by members of the public. Most of the bats in our study (90 percent) were synanthropic species, those that live near humans.

Reflecting these close contacts, another 25 percent of the bats in this study died from blunt force trauma, such as being hit by a car or garage door.

Interestingly, the bats that died in this way were most often male. It’s not entirely clear why this is, but research shows that men can fly farther than femalesmaking them more likely to collide with cars or buildings.

Understanding gender differences in death is useful because it can inform conservation and management. For example, determining where bats fly and how far can determine where to build new roads. Creation wildlife crossings in busy areas with bats can also help reduce mortality.

Incomplete picture

Studying wildlife is not easy. Bats live in a variety of places, from caves to barns and attics, and scientists cannot observe bats in all places all the time.

Reports from communities contribute to the collection of bat information and help us understand the health of local bat populations.

To study bat mortality, we use an approach called “passive observation” where the public is an important partner in research. Those who find sick or dead wildlife can report it online to the Canadian Wildlife Co-operative using this tool. In BC, you can report bats specifically through The BC Public Bat Program. You can also learn more about creating habitats for bats at A guide to bat-friendly communities.

This article is based on research conducted by Western College of Veterinary Medicine student Imara Beatty of the British Columbia node of the Canadian Wildlife Cooperative.

By Kayleigh Byers – Regional Deputy Director, British Columbia Node of the Canadian Wildlife Cooperative; Simon Fraser University Research Fellow