Swifts in the chimney: What to know about this threatened bird species

Since the beginning of spring this year, Gallery 78 on Queen Street in Fredericton has seen some unusual visitors, as about 14 birds have made their way inside the building, said staff member Sophie Theriault.

"It is an old building and we've dealt with some, you know, different things over the years, like some bats … So it does come with the territory," said Theriault. 

"But there were a couple times where we'd see these kind of dark shapes, didn't really know what they were, and they were flying to and from different rooms. And then we discovered that they were chimney swifts."

The private art gallery has a large brick chimney, the perfect home for the birds.

Theriault said each time one would come in, a co-worker would gently bring the bird outside. By the time the 10th or 11th bird came through, she said a man came in and told her he was looking outside and noticed chimney swifts.

He was part of SwiftWatch, a program by Birds Canada, and from there Theriault said the gallery started working with the group to find out what to do about the swifts coming in through the chimney.

Chimney swifts are unique when it comes to habitat says Graham Sorenson, the Atlantic aerial insectivore conservation program co-ordinator for Birds Canada.

"Historically, in North America, chimney swifts would have been breeding in large hollow trees," said Sorenson.

"As early settlers arrived and began clearing a lot of older forests that would have had these mature trees, and also at the same time [started] building towns with brick chimneys, chimney swifts lost their natural habitat and, pretty readily it seems, adapted to using chimneys."

Now, chimneys are their primary nesting spot, he said.

Chimney swifts are built differently than most bird species, he said, because they're unable to perch on branches and can only cling to vertical surfaces.

The birds will collect one twig at a time in early June and fly it into a chimney, where they will use saliva to glue the twig to the wall, said Sorenson. They repeat this process until they have a small nest attached to the wall to lay their eggs in for summer.

Sorenson said it's actually not common for chimney swifts to venture inside buildings. But occasionally, if there are openings, especially in older chimneys, they might find a way out that looks like the way they came in.

If chimney swifts are nesting in your chimney, Sorenson said, it's best to leave them be.