Endangered black swifts nesting along popular Banff trail at highest levels in 17 years

CALGARY -

The endangered black swift has returned to Johnston Canyon in numbers not seen since 2004.

A total of five nests were documented at the popular landmark this year, one of just two places in Banff National Park where the very particular bird is known to lay its single egg.

"There may still be other sites out there, so far in the last two seasons of putting in an enormous amount of effort to reach some of these very remote sites, we haven't uncovered any others," said Jennifer Reimer, a Parks Canada biologist and the black swift project lead for Banff.

"In Johnston canyon in particular, we had up to 12 nests until about the early 80s and then that dropped off quite steeply after that, and that was simultaneous with a lot of other aerial insectivores that were declining as well."

The endangered birds only nest in canyons near waterfalls. They choose nest sites with shady, sheltered pockets and plenty of moss. They are in the mountain parks between roughly late May and early October, although this year's nesting birds left around Sept. 18.

Because the relatively small adult birds can spend days at a time high in the air catching insects, surprisingly little is known about them. But researchers say populations have fallen roughly in half since the early 1970s.

They attribute the decline to a drop in insect populations, which may be tied to airborne pollutants and pesticide use.

The young birds face a daunting first flight -- within a week of growing flight feathers they leave for Brazil where they spend the winter.

Johnston Canyon has strict regulations in place to keep people on the established trail system throughout the nesting season. Maximum fines reach $25,000. In 2019 dozens of tickets were given out to violators.