By Steve Hubrecht

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There is no doubt that encroachment affects wildlife, some species move off and some turn human structures into homes. Sunken Second World War shipwrecks becoming artificial reefs is one  happy accident. Another, much more local, example is the dirt pile by the Athalmer boat launch — now home to a nine pairs of breeding bank swallows.

The dirt pile has sat in Athalmer for more than three decades, but it wasn’t until last year that a volunteer bird monitor realized it was habitat for the at-risk species. Now the pile is an official habitat protection project for the District of Invermere. The birds face danger from loss of habitat and exposure to pesticides in their diets, according to Nature Canada.

swallows at their nests in the sand wall

The project involves preserving the one-third of the pile the bank swallows are using, creating fencing barriers to keep people a safe distance away from the birds, and adding interpretive signs explaining the ecological significance of the species and their importance of bank  swallows to the Shuswap Band and the Ktunaxa Nation.

Golden-based wildlife biologist Rachel Darvill spearheaded the efforts.

Darvill leads the Upper Columbia Swallow Habitat Enhancement Project, which focuses on bank swallows and barn swallows between Canal Flats and Kinbasket Lake. Both species are designated as at-risk in Canada. 

Volunteers with this larger project do inventory of bank and barn swallow nesting sites. One Columbia Valley volunteer noticed banks swallows living in the dirt pile west of the boat launch and south of the boat launch parking lot in Athalmer.

Invermere planner Rory Hromadnik said he didn’t know exactly how long the dirt pile has been sitting in Athalmer, but said it was part of the original resort development proposal at the site, and so likely dates to the 1980s.

The development was never complete, but “people were protesting down there, because they were filling in the wetlands,” he said. The dirt pile was probably being used by the developers for compaction, he added.

The two-thirds of the pile that the district removed amounts to 3,000 cubic metres and will be used for landscaping or the natural amphitheater in the planned park, said Hromadnik.

Darvill came to investigate and identified nine breeding pairs (18 adults in total). She soon found out that the part of Athalmer containing the dirt pile is to be redevoped. The pile is part of the Lake Windermere Resort Lands, which the District of Invermere bought in 2019 and which it plans to turn into public parks and other green space.

She contacted the district and proposed not only conserving the pile, but also enhancing it as habitat. As far as the swallows are concerned her timing was excellent, since the district had initially planned to remove the entire pile and use it elsewhere on the site.

“It was lucky. They were going to destroy it,” she said.

Darvill couldn’t say with certainly how often bank swallows use manmade dirt piles as habitat, but explained that from what she understands it’s not very common.

The reason she’s not certain is because there is not a lot known about bank swallows in general. Darvill said she was not aware of any research on bank swallow colonies in urban habitats, and her experience in the Columbia Valley is that most of the bank swallow habitat tends to be on the lakeshores or in steep banks of the Columbia River.

In fact there are “not a lot” of bank swallow colonies north of the steep river banks on the Columbia north of Brisco, she said. Still, Darvill was clear that any bank swallow habitat that can be preserved should be. The species suffered a 93 per cent decline in population in Canada between 1970 and 2010.

Lake Windermere supports  a “significant amount of bank swallow habitat,” she said. But one of the swallows’ favourite nesting site on the lake — Lake Windermere Provincial Park — has also recently seen a drop in nesting.

At one point Lake Windermere Provincial Park supported 260 documented bank swallow burrows. A few years ago there were only four nesting pairs occupying those burrows. Part of the problem was  people using the park for recreation and disturbing the birds.

“There was a trail right through the colony, which caused some slumping. And people were coming right up to the nests and jamming sticks in the burrows,” said Darvill. “It was quite a bit of negative impact.”

The nesting areas at Lake Windermere Provincial Park have since been fenced off and signs put up telling the public to stay away.

The swallows probably chose the dirt pile in Athalmer because it is the right soil type. “Friable soil” has crumbly texture, and bank swallows like it because it is not too hard to dig in, but is still hard enough to retain its shape, said Darvill. 

The pile will be enhanced as habitat by making the small vertical face where the bank swallows have burrowed into a more distinct vertical face.  Bank swallows likely prefer vertical faces because this makes it hard for would-be predators to get at the burrows, said Darvill.

The bank swallow habitat project “fits very nicely” with the district’s plans for the area, he said. This includes the park as well as Invermere’s planned trail network expansion.

People will be able to read about bank swallows, see the habitat project, and then look across the Columbia River at the bank swallow burrows on the other side, he explained.

“It’s a neat opportunity and will be a great educational piece,” he said.

The project is set to be complete before mid-May, when bank swallow breeding season begins.

The total cost for the project is $22,500 — $5,000 from a grant and the remaining $17,500 from district reserves.