Most Canadian bat boxes are empty, and this researcher wants to know why

There is not much hard information on how to create a successful bat box in Canada, but Karen Vanderwolf is looking to change that with the Canadian Bat Box Project.

The boxes are artificial roosts that give bats a safe place to stay, and also help encourage bats into areas where there aren't many. They can be put up attached to trees or buildings, like a house or shed.

The project has signed up about 1,000 people. Vanderwolf, a researcher at Trent University, said only about 20 per cent have successfully attracted bats to their boxes.

"It's quite a low success rate," she said.

"I'm hoping to generate better recommendations to increase that success rate."

Most of the literature on bat boxes is based on research in the United States and Europe, said Vanderwolf, where the climate is very different. Bats are very particular about the temperature they like to roost in, between 27 C and 35 C.

Early results of research suggest that some bat boxes in Canada are, not surprisingly, too cold to attract bats.

"The new problem, that we just became aware of, is that some boxes, even in the Yukon, are too hot," she said.

"They're going over 50 degrees, which is lethal for the bats. So we need to find out what designs and placements of bat boxes in Canada are ideal for our bats."

Counting bats

The Canadian Bat Box Project will run for three summers, starting this year, and it is not too late to sign up.

Participants start by filling in an online questionnaire about their box, including things like size, and whether it is attached to a tree or a building. And then follow up with whether you have success attracting bats.

"Shine a light up into the box in the summer to see if there's bats there," said Vanderwolf.

"If you do have bats it would be nice to know how many bats, and that involves doing what's called an emergence count, so sitting by your box at dusk for about an hour and counting bats as they exit your box."

Vanderwolf would like to see people putting up larger bat boxes with more than one chamber, which can house several hundred bats.

The project will provide equipment to measure the temperature in the box, as well as for collecting guano, which can be used to identify species. Vanderwolf believes the only species that will use boxes on P.E.I. are little brown bats.

The ultimate goal of the project is to determine the perfect design and placement for boxes in Canada to encourage bats to roost and reproduce, and grow the population.

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