- August 13, 2011 - Biodôme : Animal portrait
While not represented at the Biodôme, birds of prey are nevertheless an essential element of forest ecosystems. So this is a great opportunity to talk about the diurnal birds of prey that call the Laurentian maple forest home.
Speed out in the open
Not all birds of prey are adapted to hunting in a forest environment. The peregrine falcon (Falco peregrinus) can dive spectacularly, at a speed of 130 to 180 km/h—and sometimes in excess of 300 km/h—swooping down on its unsuspecting victims, such as pigeon-sized birds. Its narrow, pointed wings are perfectly adapted to flying at great speed, ideal for catching birds in flight by surprise. This hunting technique is perfect out in the open (fields, clearings, marshes), but completely unsuited to the dense maple forests of southern Québec. On the other hand, the merlin (Falco columbarius) is found in forested areas, but generally further north in more open coniferous forests, such as the La Vérendrye wildlife reserve.
Gliding and ambush
Hawks are known for their ability to use rising air currents to soar high above the ground. They can be seen with their wings outspread and unmoving, circling tightly as they ride these bubbles of hot air. Some, such as the red-tailed hawk (Buteo jamaicensis), hunt in the open. It chooses a perch—a high, protruding branch on a tall, isolated tree or one on the edge of the forest—as a lookout and a launchpad when it sees potential prey. This hunting strategy works equally well for catching rodents and other mammals as for birds on the ground. The red-tailed hawk is a species that has benefited from humans’ disturbances of nature (fields, roadsides, deforestation). Its range has expanded and its population is currently on an upswing. Some hawks are essentially forest-dwelling. This is the case of the red-shouldered hawk (Buteo lineatus) and the broad-winged hawk (Buteo platypterus). The broad-winged hawk is by far the more numerous of the two species. It is often seen circling high above the treetops; it would easily go unnoticed but for its distinctive cry that resembles its French name, petite buse: “tit buuuuse.” According to the Cornell Lab of Ornithology, flying above the forest canopy may be a way of delineating its territory. Like the red-tailed hawk, the broad-winged hawk hunts by ambushing its prey. From its forest perch, it waits for a chipmunk, a shrew or even a toad to pass by. In fact, the broad-winged hawk likes frogs and toads so much that it is often spotted in forests near water (rivers, lakes, marshes). The Cornell Lab of Ornithology suggests that the broad-winged hawk’s taste for amphibians—which are cold-blooded—may explain why it is among the first raptors to migrate in the fall. It also makes the longest migration of all Québec’s raptors, and it is the only one to spend the winter in the tropical rainforest (as far south as Colombia).
Forest obstacle course
Birds in the Accipiter genus—mostly known as goshawks and sparrowhawks—are the champions of hunting in the forest. Québec’s deciduous forests are home to the little sharp-shinned hawk (Accipiter striatus) and the powerful northern goshawk (Accipiter gentilis). The medium-sized Cooper’s hawk (Accipiter cooperii)—another species typical of this habitat—is much rarer. Short wings and a long, narrow tail give accipiters great manoeuvrability among the tree trunks and underbrush, making them unrivalled hunters of woodland birds. Should the target take flight and attempt to escape, these birds of prey can sustain a very close chase. The sharp-shinned hawk can therefore feed on the whole range of small birds found in the Laurentian maple forest, including sparrows, finches, warblers and robins. The northern goshawk prefers a heartier meal of ruffed grouse or snowshoe hare. But it won’t turn down squirrel or blue jay as an appetizer. Accipiters are even more discreet than the sharp-shinned hawk—that is, unless you happen to pass close to their nesting site (as early as April for the northern goshawk), in which case they become very aggressive. The northern goshawk is the largest and most aggressive accipiter. The Canadian Wildlife Service’s accipiter fact sheet, mentions that the northern goshawk will not tolerate intruders approaching closer than one kilometre to its nesting site! An exaggeration? I can personally testify that it is not! Thankfully, the northern goshawk generally chooses quiet, secluded areas of the forest to make its nest.
Birds of prey are among the select group of animals at the top of the Laurentian maple forest food chain. High-level predators must patrol large areas of the ecosystem to find enough food for themselves and their offspring. They can therefore never be very large in number. Observing birds of prey is always fascinating and a rare privilege, as you never know when an unexpected visitor might appear.