Calgarians running, cycling and walking along river pathways might notice the large brown and white osprey – sometimes called fish hawks – hovering over the river, diving deep to catch a fish before flapping off to a nest towering above, affixed to a wooden pole.
Few realize how close we came to losing this summer spectacle.
In 1976, authors Ray and Jim Salt of The Birds of Alberta described osprey as “one of several species whose future existence is uncertain” explaining that “relentless persecution of all hawks during the first half of this century resulted in the disappearance of osprey from most settled regions.”
Then, during the 1950s and 1960s, DDT usage caused thinner egg shells that broke before hatching. This resulted in the Salts’ dismal outlook for this bird of prey.
Colin Weir, cofounder of the Alberta Birds of Prey Foundation, has been rescuing birds for 40 years. He has seen tremendous change in people’s perception of raptors.
“The thought these days of birds of prey being shot I think is horrific to everyone. It’s a good demonstration of the value of environmental learning and how it can change people’s attitudes towards wildlife,” Weir said.
Worldwide action to limit DDT use started in 1972, allowing birds of prey populations, including osprey, to recover.
Records from Nature Calgary’s May Species Count of an 80-kilometer circle from the Centre Street Bridge show osprey populations grew from 0 in 1979 to 41 in 2021.
“Overall, it is clear that the number of ospreys in the city and in the total count circle has greatly increased since 1979,” said Nature Calgary’s president, John McFaul.
Ospreys get pole position
Possibly the seeds for Calgary’s osprey resurgence were planted in 1994 on a wooden pole at the Calgary Zoo.
Brian Keating, owner of Great Big Nature and former Head of Conservation Outreach at the zoo, recalls a neighbour calling about osprey trying (and failing) to build a nest atop a high-voltage transmission tower. They asked if something could be done.
Keating called a contact at Enmax Corporation who donated an old utility pole and a back-hoe to plant it. He hastily built a platform and attached branches he found dumpster diving after a neighbour trimmed their apple tree.
“This was at a time when ospreys were just coming back from a very precarious level of populations,” Keating said.
“As we raised that pole, ospreys were circling above us. As we were driving away, I looked back, and an osprey was landing on the nest. They were desperate to lay their eggs,” Keating recalled.
Enmax was reluctant to take credit, as helping birds could have seemed frivolous given budget pressures. Since then, utility companies have realized nest platforms avoid costly fires and power outages.
“We have some pretty healthy river systems, and artificial nests are another big reason osprey are doing really well,” Weir said. Currently there are 19 nest platforms in Calgary.
Platforms part of enviro focus for Enmax
Alison Anaka, Environment Specialist with Enmax said their osprey platforms are a part of their overall environmental focus.
“The platforms protect the birds, keeping their nests out of harm’s way while ensuring the continued delivery of safe and reliable power to our customers,” she said.
Enmax eventually sponsored a camera that beamed osprey happenings from the nest 24/7.
“We collected video clips of behaviour that to my knowledge no one had seen before. You could see the osprey walking around the egg with a closed fist so that its talons wouldn’t accidentally destroy the egg,” said Keating.
“We had a hailstorm and watched the adult bird sheltering the young with her wings, and hailstones hitting her body and filling up the platform.”
Keating’s wife Dee recorded hatchings, observing 29 chicks between 2007 to 2018. It was a testament to the species ability to rebound with suitable habitat.
The camera no longer works but people visiting the Zoo’s muskox between April and September often see osprey. Another pair have taken up residence on the Bloom sculpture on St. Patrick’s Island.
Still threats to osprey success
These ospreys no longer worry about DDT but there are new threats.
“What we see are birds getting hit by cars, and birds becoming entangled in baler twine. It’s a netting they put around round (hay) bales. It’s colourful, light, and like a prize find for a nesting osprey,” Weir said.
FortisAlberta helped save an osprey in 2020 that was entangled in twine, hanging upside down under the nest platform until help arrived.
That story had a happy ending. Weir wondered how many other nests is (entanglement) happening that we don’t know about?
McFaul said there are still other factors to consider.
“Breeding success and conditions on their wintering areas and migration paths will play a role (in number of birds seen in Calgary),” he said.
Soon the osprey will start their migration to Central and South America.
Still, Calgarians can pass winter knowing osprey will be coming back.