LAKE LOUISE – AltaLink is taking an osprey family under its wing in Banff National Park.
The electricity transmission company will shut off power on the 551L power line from midnight to 6 a.m. on Oct. 9, affecting all areas in the park west of Sunshine Village to Lake Louise in order to relocate the nest from a dangerous part of its transmission line. Sunshine ski resort and the Banff townsite will not be affected.
Nikki Copeland, AltaLink’s senior environmental advisor, said an artificial nesting platform on the same structure the osprey have chosen for their nest will be built to ensure safety of the osprey and the transmission system.
“Moving the nest from unsafe energized equipment to the new location will allow them to return to the same nest and will help ensure the reliability of the transmission system,” she said.
The company found the nest on one of its structures in the Johnston Canyon area during a routine patrol.
How AltaLink deals with osprey nests forms part of its avian protection plan.
Osprey pairs, which mate for life, work together to build a large stick nest on a tree, cliff face, or man-made structure, often power poles, in open areas. They each have their roles to play in incubating, brooding, and caring for their young.
Whatever the location, osprey nesting habitat must include access to fish, gravitating towards shallow fishing grounds.
“Osprey are very interesting birds and have a very high affinity for their nest site and that means they return to the same site year after year, so the same nest site will persist for generations of osprey,” Copeland said.
“Because of that high affinity, if you remove the nest off of a power line structure, they’re just going to continue to try to re-nest, and if you try to just install a deterrent again, they’re going to try to overcome that and continue to try to nest there, or they might move to the next structure, which might be dangerous.”
From a power line company’s perspective, Copeland said depending on the location of the nest and the type of structure, it can increase the risk of wildfires and power outages.
“So there’s now a risk for wildfire if that nest catches on fire and there’s a safety and liability impact,” she said.
“We call it tripping up the line … that would also knock out the power and would affect everyone that replies on that power line for their electricity.”
However, Copeland said many of the places ospreys build nests throughout the company’s system are safe.
“If you see an osprey nest on a transmission tower, there’s actually no risk,” she said.
“However, if a nest is right over top of an energized part of the power line structure, then it can now be a risk to safety, liability and the ospreys themselves.”
This is the second osprey nest AltaLink has relocated in recent years in Banff National Park.
In this case, Copeland said the artificial nest platform is about 3.5 feet by 3.5 feet and will be extended off the existing site.
“What we do is we take the original nest and we use UV-rated zip ties to tie it down to make sure it's secure,” she said.
“We put covers over the energized parts of the power pole structure, so if the ospreys drop sticks or approach it, then it keeps them safe as well as the equipment safe.”
Osprey numbers crashed in the early 1950s to 1970s in North America, when pesticides poisoned the birds and thinned their eggshells.
Studies of the raptors provided key support for wider legal arguments against the use of persistent pesticides and after the DDT ban in the United States in 1972, populations rebounded. In Canada, DDT use was suspended in 1985 and the use of existing stocks was permitted until the end of 1990.
“They were severely affected by DDT in the 1950s and their numbers plummeted,” Copeland said.
“At the same time is when a lot of power lines were being built, so with eradication of DDT and with introduction of power lines on the landscape, they very quickly discovered that that was a great place to nest.”
Scott Schreiner, vice president of external engagement for AltaLink, said the company understands that any work requiring an outage is disruptive to local residents and businesses.
“That’s why we’re completing the work in the middle of the night to reduce the inconvenience,” he said in a news release.
