Unofficial trail in 'secret cave' area of Johnston Canyon closed by Parks Canada to protect unique birds

In an effort to entice a unique bird population back to Johnston Canyon in Banff National Park, Parks Canada has closed a popular — but unofficial — trail.

There used to be up to 15 nesting pairs of black swifts in the canyon, but today there's just 1 or 2

The trails around the waterfalls of Johnston Canyon (shown here in 2015) are some of the busiest in the Rockies. (subindie/Creative Commons)

In an effort to entice a unique bird population back to Johnston Canyon in Banff National Park, Parks Canada has closed a popular — but unofficial — trail.

Bill Hunt, resource conservation manager with the park, told the Calgary Eyeopener on Friday that the black swift population at Johnston Canyon — in an area known to locals as the "secret cave" — has been declining in recent years.

"What we've seen is there used to be upward of 14 or 15 pairs nesting in the canyon, right now there's typically one or two pairs, and I think last year there was a single fledgling that we think survived," Hunt said.

"So protecting the few birds that are there is critically important."

Black swifts — which are mostly found in coastal regions but also nest in canyon habitat in the mountains — lay one egg at a time, typically in May.

It takes nearly a month for the egg to hatch, then unlike most other birds, the young don't fledge — grow feathers needed for flying — for another two months.

"They're provisioning young on the nest all the way through July and August and even into September, which is really unusual for a nesting bird," said Hunt.

"Most birds, especially in the Rockies, are quick to get their young out of the nest and flying and foraging, so the parents have a really big job to do in terms of caring for that young all through the summer."

Declining numbers

Johnston Canyon is the only known nesting site for black swifts in Alberta.

Hunt says the main trails at Johnston Canyon — about 20 kilometres west of Banff — are not affected by the closure. Johnston Canyon and the Ink Pots are some of the busiest trails in the Rockies, with hundreds of visitors a day in prime tourist season.

"The area that has become popular is actually off the official trail, down in the canyon," he said.

"It's actually a large overhang, it's a bit of false advertising to call it the secret cave, but that's the name that has happened on the internet. It's a very scenic spot and so people tended to wander off trail. Pictures from that spot got posted online and within a very short time period, within the last few years, there's a trail now beaten down in there to get into that site. We've had a lot of graffiti and that sort of thing in there as well."

'Little fighter jets'

The largest member of the swift family, Hunt described the birds as looking like "little fighter jets."

"They look similar to swallows, if you saw one on the wing you might think you're looking at a swallow," he said.

"They have very long, pointy wings, a notched tail, and … a short, stiff, wing beat."

Swifts are known as aerial foragers.

"They spend most of the day out building up a mass of saliva and bugs in their throat, then come back and provide that to their single chick," said Hunt.

The trail closure is in place until Nov. 15 and could be in place again next year. 

"We don't want to affect ice climbing and by then the birds are gone," said Hunt. "The canyon will be open again for ice climbers this winter and we'll reassess next summer and determine what's appropriate."

With files from the Calgary Eyeopener