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Mid-Island's largest bat colony roosts under community care

Latest count tallied 1,800 bats in the North Oyster Community Centre near Ladysmith.
An average of 1,823 bats emerged for the maternal colony's first count of the season in June.

The largest bat colony on the central Island now averages 1,800 little brown myotis bats, an increase of almost 300 from last year's count.

Situated in the attic and bat boxes of the North Oyster Community Centre in Ladysmith, the tiny mammals have formed a maternity colony, entirely made up of female bats and their young pups. 

"I would say pretty confidently it's the biggest roost [on the mid Island], it's absolutely the biggest roost we know of," said Linda Brooymans, NALT's stewardship manager and mid-Island coordinator for the B.C. Community Bat Program.

While the population provides valued ecosystem supports such as insect control and providing nutrients via guano, two summers ago the colony almost lost its home. In 2022, the North Oyster and Area Historical Society, which runs the centre, considered blocking off the attic, limiting the bats to the boxes at the side of the building. 

A study at the time aimed at research on bat boxes found that the community centre hosted a population of more than 900 bats, and years of being home to such a large colony had turned the attic into a mess of guano.

During discussions, Brooymans spoke to the board on the importance of the roost.

"When you exclude bats from a roost like that, even if you have boxes … often only a portion of the bats will use the boxes and the rest, we don't know where they'll end up," she said. "Especially since these... attic roosts can be really important for maternity colonies because there's all these different temperature gradients within which is really important for these little baby bats."

The board was moved by her words and the majority voted to save the little mammals. Since then, the attic has been completely refurbished to allow for easy cleaning that takes under 40 minutes, thanks in part to a grant by the Habitat Conservation Trust Foundation as well as local donations. The guano produced by the bats is then sold locally as fertilizer. One board member, Isabel Bunning, credits it for saving her strawberries.

"We had a very poor crop of strawberries for a couple of years. So we decided to transplant them, put some new soil down, put all these plants in and sprinkled with guano. I think it's very successful," she said. 

Regular summer counts are spearheaded by Kathy Doyle, treasurer with the historical society, along with help from Brooymans. Money raised from the sale of the guano is also used in the bat stewardship research.

"That will give us more money because we want to get a camera," Doyle said. "It will be used so you can see the bats are healthy, when they come and when they go."

The first count of the season took place on June 8, bringing about a dozen local volunteers who were each supplied with a clicker. Each volunteer was paired up and put in charge of a different "zone." One zone is the main roost, others include the less-populated boxes. At 9:08 p.m. the bats began emerging, commencing the hour-long count. 

At its height, the air was filled with little squeals and the sound of clickers pressed in rapid succession as volunteers kept their eyes firmly onto the different exit areas. Rather than emerging at once, the bats came out a few at a time, scattering in all directions.

By the count's end at 10:08 p.m., the majority had flown into the trees, a few sticking around to catch mosquitoes. 

There are three more counts planned for this summer with the next taking place on Thursday, June 20. While anyone is welcome to view the bats or volunteer during counts, the centre discourages people visiting on other nights.

Those who want to volunteer or purchase guano are asked to e-mail

Jessica Durling

About the Author: Jessica Durling

Nanaimo News Bulletin journalist covering health, wildlife and Lantzville council.
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