In recent years, the bat has been gaining allies, particularly among acreage owners, farmers, ranchers and environmentalists, says Dave Hobson, wildlife biologist with Alberta Fish and Wildlife.
“Certainly over the years, people’s attitudes towards bats have changed,” said Hobson.
“In the past, I used to get calls from people saying, ‘I’ve got bats in my house. What kind of poison can I use or how can I kill them?’”
“Now, most of the calls I get are, ‘we’ve got bats in our house … but we don’t want to kill them. Can we set up bat houses? How do we get them to move?’”
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In particular, rural property owners appreciate bats for their finely-tuned hunting skills and their voracious appetites.
Depending on the species, a single bat can consume up to one half of its body weight in flying insects in a single night.
To locate its prey, a bat emits a series of high-pitched sounds that are inaudible to the human ear.
The sound waves bounce off the flying insects as well as stationary objects and serve as a built-in guidance system for bats.
“The most obvious benefit is insect control,” said Tara Tamasi, director of wildlife care with the Alberta Institute for Wildlife Conservation.
“They eat tonnes of insects and their (feces) is excellent fertilizer as well.”
According to Hobson, there are at least nine bat species residing in the Canadian prairies, the most common being the little brown bat which numbers in the hundreds of thousands.
Nine species are known to live in Alberta. Saskatchewan is home to seven or eight species and Manitoba has six.
All species that live in the West are small, insect-eating species that are rarely seen during the day. They hunt in the evening or at night and spend the daylight hours hiding out in dark, secluded spots.
Canada’s bats are migratory.
Some species fly south for the winter to warmer climates in the United States and Mexico.
Others spend the winter in Canada but will typically hibernate in caves or rock crevasses.
Bats preparing for hibernation will often congregate in mountainous regions of British Columbia, Alberta or the Northwest Territories where temperatures are moderate and caves plentiful.
Dark, cool locations with temperatures slightly above freezing and high humidity are ideal for hibernation.
In the summer, bats typically prefer locations where food is plentiful, often roosting in rural areas near rivers, lakes, streams, sloughs, potholes and marshy areas where insect populations are high.
During the summer, they will roost in trees, chimneys, abandoned buildings and attics.
Females prefer warm, dry locations for raising their young. This explains why bats will often take up residence in the attic of a house, if access can be gained.
People concerned about bats residing in their chimneys or attics are encouraged to wait until late in the year, preferably October or November, before restricting access. By then, newborns have matured bats and adults have migrated to wintering grounds.
To ensure safe relocation and minimize bat mortalities, Tamasi’s organization will assist with bat relocations in Alberta.
For information on that service, call the Alberta Institute of Wildlife Conservation at 403-946-2361.
According to Hobson, there is growing recognition that bats serve a useful function that is beneficial not only to the environment but also to the to agriculture and forestry industries.
“Worldwide, bats eat a lot of things. There are some that eat fruit, some that eat nectar, some that eat meat and some in South and Central America that drink blood,” he said.
“But in Canada, all the bats that we have are insect eaters … and a lot of the food that they eat are moths and beetles (which) can be major agricultural and forestry pests.”
Property owners can attract bats by providing suitable roosting sites. Man-made bat houses can be constructed at minimal cost with a few basic materials.
For best results, the houses should be attached to poles, trees or buildings and positioned about four to five metres above the ground. Ideally, they should be located in areas that receive ample morning sunshine and shade in the afternoon.
Houses with exteriors that are painted flat black will absorb and retain heat more effectively, increasing chances of occupancy.
Typically, bats that roost in man-made bat houses will use them as short-term day roosting sites, although some bat houses may be used as maternal nesting sites.
There is little evidence to suggest that bat numbers are declining in Western Canada but according to Hobson, bat species are facing challenges.
“At this point in time, the main problems for bats, at least in this part of Canada, are things like wind farms, changing forestry practices and potentially the loss of old buildings that are suitable for roosting,” Hobson said. “But generally, if you put up a bat house … especially if they’re located close to water bodies … and if you get them up high and face them to the south … chances are good that bats will start using them.”
Bat houses can be constructed in a variety of sizes but should be made with rough-hewn wood to accommodate climbing.
Sides and top should be airtight and the bottom should be partially enclosed with a narrow slot, about three-quarters of an inch wide, for entry. Detailed instructions on constructing a bat house are available on the internet.
