Would you give up your favourite climbing route if it meant protecting an endangered species?
Most climbers in the Bow Valley are happy to do just that.
Nesting peregrine falcons, almost extinct in Alberta about 50 years ago and still rare in the Bow Valley, have led to the temporary closure of a popular climbing route on Mount Rundle near Canmore.
Alberta Parks closed the North Ridge 5.8 climbing route on the East End of Rundle to protect these birds.
Peregrine falcons like to nest on cliffs, and while they haven’t affected other climbs nearby, this route is off-limits for now.
Jeff Moore, who is the president of the Bow Valley Climbers Access Society, said that climbers are okay with the closure to help protect the peregrines, which are still considered a threatened species in Alberta.
“For wildlife and birds, climbers are pretty easy going. Our community is pretty lucky to have so many alternative climbing routes. It’s not like there’s not other routes on the East End of Rundle to choose from that are also great quality.” Moore told the Rocky Mountain Outlook.
Peregrine falcons used to nest along most of Alberta’s major rivers. However, in the 1950s and 1960s, their numbers dropped because of pesticides like Dichlorodiphenyltrichloroethane, or DDT for short.
DDT is a chemical pesticide that was widely used in the mid-20th century to kill insects, especially mosquitoes that spread diseases like malaria in tropical countries. While it effectively controls pests, it also harms the environment and wildlife.
DDT builds up in the food chain, leading to animal health problems, especially birds like peregrine falcons.
When small birds ate insects contaminated by DDT, some pesticides remained in their bodies. When peregrine falcons preyed on these small birds, the DDT built up in the falcons’ bodies at an even higher rate.
This contamination affected the female falcons’ ability to lay healthy eggs. Their eggs lacked calcium, which meant they were thin-shelled and weak, causing them to break under their parent’s weight.
DDT was banned in 1972, and with the help of breeding programs, the number of peregrine falcons in Alberta has grown from just two or three pairs in 1970 to around 65 to 75 pairs today.
On The Mend
Because of this recovery, peregrine falcons were moved from the “endangered” to “threatened” category in 2000 because their population was growing, there were fewer pesticides in their bodies, and they were reproducing better.
Jason Rogers, a bird expert and biologist, supported the decision to close the climbing route to help the falcons.
He said peregrine falcons have been seen very little in the Bow Valley except during migration or after breeding season. But, even though there are more peregrines now, they still need help finding nesting in the Bow Valley.
Rogers mentioned that in the late 1980s, there was evidence of peregrines nesting on Mount Yamnuska.
He also saw what was probably a breeding pair in 2004 and noted that a pair was photographed near Castle Mountain in 2019.
Since 2022, there have been sightings of adult peregrines near Banff carrying prey, which could be a sign that they are nesting in the area.
Rogers also revealed a significant discovery-a nest with young peregrines was found in Jasper National Park this year, suggesting a potential increase in the peregrine population in Alberta.
Alberta’s peregrine falcons usually spend winter in southern Mexico, Belize, and Colombia.
However, Rogers cautioned that peregrines are not yet in the clear. They still face significant risks due to the continued use of DDT in some parts of the world, such as South America, for malaria control, and its long-lasting impact on the environment.
DDT in the soil can take between two to 15 years to break down, depending on the soil type.
“Peregrines shouldn’t be considered out of the woods yet,” said Rogers.
Mean, Lean, Peregrines
Peregrine falcons usually lay four eggs, but sometimes five. About 1.5 young falcons per pair successfully leave the nest each year in Alberta.
The eggs are laid between late April and mid-June, and the male and female birds take turns incubating them for about 28 to 33 days.
The young birds leave the nest at five to seven weeks old, with males usually leaving first. Most peregrines leave the province by early October to go to their wintering grounds.
At birth, baby peregrine falcons, known as eyases, are as helpless as most infants. However, by about three weeks of age, they can walk, marking a significant milestone in their early development. Despite this, they still rely on their parents to bring them food.
However, eyases grow incredibly fast, doubling in size in ten days. By 12 weeks of age, eyases start flying, and by 12 to 15 weeks, they begin hunting and caring for themselves.
Peregrine falcons have skills that make them incredible hunters and a force to be reckoned with in the wild.
Peregrine falcons are the fastest animals on the planet. Diving to catch prey, they can reach speeds of over 400 kilometres per hour.
What’s truly astounding is the exceptional eyesight of peregrine falcons. They can spot their prey from over a mile away, a feat that’s about eight times better than human vision.
These incredible animals mostly hunt other birds while flying. They often catch prey mid-air, using their speed and agility to outmaneuver other birds.
As apex predators, peregrine falcons hold a crucial position in the food chain. They regulate the populations of their prey and thereby contribute to the balance of the ecosystem.
Our province’s peregrine falcons may have clawed their way back from the brink of extinction, but as Rogers said, they aren’t out of the woods yet.
If we want to keep these incredible animals on our landscape, we need to combat the biggest threats to peregrine falcons, including severe weather caused by climate change and toxic chemicals like DDT.
