Peregrines return to Pembina River
Falcon pair nesting 100 metres from home of last birds in 1964
A pair of peregrine falcons has nested along the Pembina River — the first in the area for five decades — after they were driven to the brink of extinction by the use of DDT, a pesticide that was banned in 1972.
“It really calls for celebration,” said Gordon Court, a biologist with Alberta Environment and Sustainable Resource Development.
“Like many of the other peregrines in Alberta, they were pretty much extirpated from those river valleys.”
Amazingly, the pair has settled along the Pembina only about 100 metres away from the spot where the previous pair nested in 1964.
“Whatever they found attractive … obviously they still found attractive today,” Court said.
The last of the birds were captured around 1970 and taken to a facility at CFB Wainwright where they were bred and, eventually, reintroduced into the environment.
Now, the population is likely just shy of 70 breeding pairs — the target the Alberta government has set to take the falcons off the threatened species list.
The government has been trying to introduce peregrines to the Pembina River for the past three summers. That two have settled there is a major success in work to introduce the birds into wild areas; many have previously nested in cities.
“Peregrines look at the world like they own the place,” Court explained.
There isn’t a problem with the birds nesting in cities, said Alastair Franke, who studies the falcons in Arctic Canada. “They look at the highrises as basically cliffs,” Franke said.
But learning to fly can be dangerous because the birds can fall to the street. It’s “a much more lethal environment,” Franke said.
Releasing the birds into wild areas puts them in more natural habitats and helps spread them more evenly across the province. “In that regard, this new pair of peregrines on the Pembina has achieved exactly what it’s trying to achieve,” Franke explained.
When the birds are to be released, they are taken in a box to their new environment where they are fed for several days and can see outside.
“One day we just crack the door a little bit, and like most teenage animals … they go exploring, ”Court said. “Then they’ll realize that they’re free, and then they just become young birds looking for adventure and food.”
In 2015, the birds, which weigh between 600 and 1,000 grams, will be counted for a survey of nesting sites done every five years.
“What people do is jump in a helicopter, fly to those known sites,” Franke said. “There’s either a pair there or there isn’t.”
The threat from pesticides has diminished with the ban on DDT, but climate change now threatens the species in Arctic areas because of increased temperatures and more storms that compromise reproductive success, Franke said.
“It’s possible that birds that are breeding in Alberta will also experience those same new threats that birds in some areas of the north are experiencing.”