Creature Feature – Peregrine Falcon (Falco peregrinus)
The Peregrine Falcon is one of the world’s most well-known birds of prey. Distribution is widespread, with sightings on every continent except Antarctica. Peregrines enjoy a wide variety of open habitats, including wetlands, alpine meadows, and tundra.
Peregrines are large falcons, only slightly smaller than the common American Crow. Females are 20 per cent longer, and at least a third heavier than the male. Peregrines are dark coloured with a light breast and a heavily barred belly. In flight, their dark underwing is often noticeable. Plumage differences between males and females are minor.
Members of this cunning species have extremely good eyesight, even in poor light, and often do much of their hunting at dawn and dusk. They hunt by diving on their prey from great heights often reaching speeds of up to 320 km/h (200 miles/h). Peregrines hit their prey in midair striking with either their talons or with the back of their forelegs. The impact is usually forceful enough to kill the prey instantly.
Nesting sites are chosen that have an isolated protected spot near good hunting grounds, usually on a cliff or rocky outcrop. They prefer ledges 15 to 60 metres above ground, with a southerly exposure, some vegetation on the ledge, and a protective overhang above. Within the natural environment of eastern Ontario, Peregrines often nest near wetlands. As a result, their diet consists largely of ducks, grebes, rails and a variety of wetland songbirds such as blackbirds. In more built up, urban areas, the Peregrines take advantage of the abundance of city birds such as pigeons, starlings, and sparrows.
Courtship involves aerobatic flights and repeated calls; these rituals are often repeated each spring.
Peregrines mate for life but will readily accept a new partner if their mate dies. The size of the breeding territory varies from less than a kilometre to over 20 kilometres or more. They tend to return to the same nesting site or area year after year, provided that they nest there successfully.
The female lays an average of three to four eggs. Ranging in colour from creamy pink to reddish brown, the eggs are slightly smaller than chicken eggs. They are usually laid every other day and are left mostly unattended until the last egg has been laid, at which point incubation begins.
Incubation lasts 33 to 35 days from the date the first egg was laid. Typically, the female sits on the eggs. The male takes over for several short shifts through the day so that the female can hunt for herself. Eggs generally hatch on successive days. When the chicks (eyases) are six weeks old they have already grown to full adult size and are starting to fly.
Peregrine Falcon numbers became drastically reduced in the mid-1900’s due to hunting and deliberate poisoning. The largest impact was that of an insecticide known as DDT. DDT was released for use in 1945, and quickly became one of the most heavily applied insecticides around the world.
It was found that DDT disrupted the reproductive system of female birds. In some cases, it prevented them from laying eggs at all, while in other individuals, eggs were produced, but had extremely thin and weak shells. Studies have shown that some Peregrine populations in North America still have high levels of DDT.
Recent efforts with captive breeding and re-introductions are helping the Peregrine to make a comeback, so much so that by the end of the second decade of the 21st century, populations of the peregrine falcon have bounced back in most parts of the world. In the United Kingdom, there has been a recovery of populations since the crash of the 1960s. This has been greatly assisted by conservation and protection work led by the Royal Society for the Protection of Birds. In Canada, where peregrines were identified as endangered in 1978, the Committee on the Status of Endangered Wildlife in Canada declared the species no longer at risk in December 2017.
As well, the popularity of the birds for use in falconry played a role in helping their resurgence. People have trained falcons for hunting for over a thousand years, and the Peregrine Falcon was always one of the most prized birds. Efforts to breed the Peregrine in captivity and re-establish populations depleted during the DDT years were greatly assisted by the existence of methods of handling captive falcons developed by falconers.
The best time for viewing is at dawn and dusk when they are the most active.