The beaver might be Canada's national animal, but for some residents of Nuns’ Island they're becoming a nuisance.

In the last year alone, the rodents downed 200 trees. Over the years, beavers have destroyed as many as 600 trees.

They pose a risk to public security, said Verdun Borough Mayor Jean-Francois Parenteau.

“We don't have any problem with the beaver personally,” he said. “It's a question of public security. It's not small trees; it’s big trees. Two weeks ago, two trees dropped.”

The borough researched ways to repel beavers, including wrapping tree trunks in wire mesh, but that technique proved ineffective.

A few years ago the borough of Verdun hired a trapper.

What some didn't know, including city councilllor Sterling Downey, is once the beavers are trapped, they're killed.

“We're not even attempting to cohabitate. We're just saying it's a problem. Eradicate. That's not acceptable,” he said.

The trapping and killing of beavers is legal.

“You think we'd respect them more if they're our national animal,” said Alanna Devine, director of animal advocacy for the SPCA Montreal.

Devine said the traps are inhumane and pose a risk to other animals, including dogs. 

“Killing beavers in these circumstances because of a couple of trees that have fallen is not the solution. And we know what the solution is and we are offering that service pro bono to the municipality, provided it will take us up on that offer,” she said.

The city said it won't break its contract with the trapper, and that it's only used as a last resort.

“Last year we only trapped one beaver and we didn’t use the trap this year,” said Parenteau. “We didn't kill any beavers.”