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Peregrine Falcon

Speeding from the Brink

by Denny Olson

Peregrine Falcon Photo Credit: NPS

Peregrine Falcon Photo Credit: NPS

My first experience with a Peregrine Falcon was on a 35-day canoe trip through Arctic tundra. I was on the lip of a tall cliff, armed with a telephoto lens, and a Peregrine was repeatedly passing my vantage point at eye-level, with deep wing beats and incredible speed. I remember being well into my second roll of film before realizing that I was the reason for the fly-bys – that there was probably a nest just below me. I exited, a bit embarrassed at my density. Later, the developed film, shot at a high shutter speed, still showed nothing but blur. They are fast.

Falco peregrinus, slightly smaller than a crow, with very pointed wings and a dead-giveaway dark “moustache”, comes in three North American sub-species, all of which can show up around the Flathead at different times of the year. Falco peregrinus anatum, our resident nester, has a medium-gray back and rustier breast than the others; F. p. tundrius, the arctic nester, is lighter in color and larger (Bergmann’s rule: larger size at higher latitudes); and F. p. pealei, on the Pacific coast, is darker than the others to the point that the moustache looks like the lower part of a black football helmet (Gloger’s rule: darker coloration in areas of higher relative humidity).

The name ”peregrine” means “wanderer”. Arctic-nesting Peregrines migrate some 15,000 miles annually. But, just to throw a curve to those who generalize, some on the Pacific Coast and in the Aleutian Islands hunt near their nest site year-round.

Peregrine charisma, of course, comes from their “need for speed”. When cruising or migrating, they move at a modest 35 to 40 miles per hour. When pursuing aerial prey on the horizontal (small to medium birds are their staple), they can crank it up to 70 mph. But the after-burners don’t really kick in until they hunt from more than a half-mile high, and “stoop” on unsuspecting prey. In a moderate dive of a mere 150 mph, they assume a diamond shape, but when they tuck their wings tightly and elongate themselves – assuming they have nearly a mile to drop – they accelerate to terminal velocity in the 200 mph range. “Fastest self-propelled creature on Planet Earth” is not a bad claim to fame.

With these aerobatic capabilities, peregrines use a variety of final approaches, from blasting into the bird and knocking it senseless, to harassing it until it almost can’t fly from sheer exhaustion. Most of the time, they level out at ridiculous speed straight behind the prey, close distance, grab it with talons and sever neck vertebrae with their beak – so quickly it can only be seen in slow motion video.

Peregrines have eyes that are permanently focused for near vision in the center of their retina – the foveal area. Their best distance vision is actually located around the center fovea, so when they spot prey a mile away, they have to tilt their heads up, down, or to the side. When diving, that tilt of the head would drop their speed, and ability to close distance, considerably. So, they actually dive toward distant prey in a gradually tightening spiral, keeping their distance vision on the movements of prey. That way, their heads can remain in the straight-ahead posture, increasing the speed of the stoop. Even though their path to the prey is longer, they get there sooner!

Peregrines are one of the most widely distributed creatures on Earth. Aside from the Amazon basin and the Sahara, they are almost everywhere. One would think that eclectic tastes in habitat and food choices were a recipe for abundance. Not so. Peregrines, in the early seventies and eighties, became the poster child for the endangered species act. Even though their populations were reduced by 75%, they were probably never technically “endangered” because of their widespread range. The real importance of the Peregrine story is how agricultural practices in Kazakhstan or Iowa can affect worldwide populations. DDT sprayed in the Argentine Pampas can cause thin eggshell syndrome in Arctic tundra birds. Bioaccumulation of persistent chemicals in a food chain can magnify toxins by quadrillions. And, everything is, always was, and always will be, connected to everything else.

Those humbling gifts of awareness can be credited to the spectacular Peregrine falcon. We woke up, at least temporarily. DDT, Dieldrin and Aldrin were banned in the U.S. Six thousand hand-raised and transplanted birds have led to 10,000 nesting pairs in North America today – some now being media darlings nesting in the urban wilds of skyscrapers. They were fully delisted in 1999. I was honored to be an opening acts as one of my theatrical alter egos in the International Celebration of the delisting. But my fondest memories about peregrines have come from watching them, slack-jawed, drop from the sky like a bullet, and remembering the lessons they taught us.

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