May 29, 1998

GEOFF MCMASTER
Folio Staff

High on the east ledge of the Clinical Sciences Building, all is quiet. After weeks of activity around the nest site of two peregrine falcons, it appears to be abandoned. But try going up to look inside and you may be risking your life.

According to Alberta Environmental Protection biologist Gordon Court, inactivity this time of year means the female is inside sitting on her eggs, with the male perched somewhere in the distance guarding. Mess with mama, nicknamed "the Flying Scalpel," and you'll likely be given a violent warning.

"I've seen them in the arctic drive off large carnivores (like grizzly bears)," says Court, who monitors peregrines to track their movements and population levels. "The female there now is extremely aggressive. Certainly anyone on the ledge of the Clinical Sciences Building would not be very welcome."

Neither are other birds. One unlucky female peregrine tried moving in on the Flying Scalpel a few weeks ago and almost lost her head. Dr. Steve Hrudey in environmental health sciences witnessed the whole drama from his office window.

"There was a tiff going on this spring. For a few days there were three adults swooping around. One of them was sitting on top of the house, and it must have been the aggressive one who came dive-bombing in there and just knocked the other one right off. I thought she had taken her head off... it's pretty vicious."

Hrudey says visiting television crews have also riled her. "Those guys are a little naive about this... one guy got scraped up, had blood coming down his head, the whole nine yards." Court always wears a motorcycle helmet and leather jacket when working around peregrines.

Competition over three nest sites in the city -- the U of A, one on the Telus building downtown and another at Inland Cement in the west end -- is also a good sign the species is making a comeback.

  • Because of DDT contamination, by 1970 there was only one known pair of peregrines nesting in Canada east of the Rocky Mountains and south of the Northwest Territories. They had completely disappeared from the North and South Saskatchewan River Valleys.

  • DDT residue concentrates up the food chain, with peregrines near the top. The pesticide collects in the bird's fat, eventually interfering with reproduction in breeding adults.

  • The peregrine falcon was listed as endangered in 1987 under Alberta's wildlife act.

  • In Southern Alberta, populations depend on the release of captive-bred young. There are now more than 75 pairs in Southern Canada.

  • Perhaps the fastest of all birds, peregrines can reach speeds of almost 320 kph in a dive.

  • They typically nest near rivers, streams and marshes away from human disturbance.

  • Nests are usually situated on ledges of rock or clay cliffs where they are protected from predators and the weather.

  • Peregrines don't actually build a nest. They scrape out a bowl-shaped indentation in loose soil, sand or gravel on the ledge of a nest site.

  • The female lays her eggs in mid-May, and both adults help to incubate them for about 33 days. The female, however, does most of the incubation, while the male bring her food.

  • Eggs hatch in mid-June. Young peregrines begin to fly, or fledge, at 35 to 45 days.

Courtesy of Alberta Environmental Protection

Once all but gone from Alberta, the peregrine population is now on the rise, largely because of the banning of DDT in Canada in 1969. Until very recently, however, the falcon was still threatened by the pesticide when it migrated to countries in Central and South America. Now that DDT is no longer commonly used there, says Court, residue in falcon eggs has been steadily dropping, and the peregrine's future looks bright.

Court says the two adults now living on campus are likely the descendents of some 34 captive chicks released in the '70s and early '80s from the Longman building on the university farm. For some inexplicable reason, even back then, some of the fledglings took their maiden flights straight to the Clinical Sciences Building.

Hrudey noticed the first in 1991, and while the current 11-year-old male is closing in on the average 14-year life span for an urban peregrine, the nest will probably always be in use, says Court.

"Once it's established as a chosen spot, you'd have to tear the building down to make it unattractive." There must be something about the building, he says, that looks good from the air. Perhaps the ledge resembles a cliff. Perhaps the falcons somehow sense their chances of survival there are strong.

What Court does know is that it's a great place to learn how to fly. There are no great horned owls around (their main predator) and when they do happen to fall, there are enough people walking by to come to their rescue.

"It's pretty amazing -- at about 40 days of age most of them do pretty well flying. But it's like giving a 12-year-old kid one of those Kawasaki Ninja motorbikes -- they have all the equipment to go 250 miles an hour, but no knowledge of how to use it." Court says if the chicks fly off the building in a good wind, they can hit speeds of 100 miles per hour. Unfortunately, they often collide with something. Roughly half of them perish in their first year.

If all goes well, this new clutch of chicks will hatch by mid-June, when Court will once again don protective gear to place bands on them. By the end of July, the fledglings will take to the air.

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