About raptors, the birds of prey
- All raptors have strong, hooked beaks for tearing flesh, and strong feet and talons for grasping and holding prey.
- In most raptor species, females are larger than males.
- Raptors possess excellent eyesight. The sharpness of vision of some species is estimated to be about eight-times greater than that of people. Thus, raptors are able to detect small movements on the ground from great heights.
There are two major groups of birds of prey, or raptors, in the world:
- Order Falconiformes - The largest group. Birds in this group are active during the day (diurnal).
- Order Strigiformes - Birds in this group are adapted to hunt their prey at night (nocturnal) Owls make up this bird order.
Order Falconiformes: the diurnal raptors
Diurnal raptors found in Alberta can be divided into three broad groups:
- Woodland hawks (accipiters)
- Heavy-bodied hawks (buteos) and eagles
The northern harrier, turkey vulture, and osprey are three Alberta raptors that do not fit into these groups.
Only falcon and accipiter hawk species are presented here. The buteos, eagles, northern harrier, turkey vulture and osprey
are treated in a separate series. See:
Falcons and Accipiter Hawks
The falcon species found in Alberta include:
- Falcons have a tooth-like projection behind the hook portion of the beak, lacking in other raptors.
- Falcons are the easiest group of raptors to distinguish in the air, as they are built for speed in flight. They have long pointed wings and narrow tails, which enable some birds to reach diving speeds of up to 300 kilometres per hour (190 miles per hour).
- Falcons do not have the large surface area on their wings that enable buteos (large hawks) to soar with ease. Instead, falcons fly with rapid wing beats. Their smaller wing surface enables them to slip through the air with a minimum of resistance.
- Falcons seldom hover (exception: American kestrel), and only the prairie and peregrine falcons soar on updrafts of warm air.
- In the air, falcons kill their prey by delivering a blow with their talons. Occasionally the hooked and toothed beak is used to kill prey on the ground by severing the spinal cord at the back of the neck, after the victim has been stunned by a blow from the feet.
The accipiters, or woodland hawks, found in Alberta are:
- Accipiters are hawks adapted for flying and hunting in woods. They have short, round wings and long tails, which permit greater maneuverability among trees.
- Their ability to fly between tree trunks and branches with little noise enables them to closely approach their prey. They are seldom seen in open areas.
- Accipiter hawks hunt birds, squirrels and mice in wooded areas.
As winter approaches, the amount of food available to raptors decreases. Ground squirrels hibernate, snow covers the activities
of mice and insects are inactive. Like many other birds that breed in Alberta, most species of raptors migrate southward
in winters to areas where food is more easily obtained.
Among falcons and accipiters, there are exceptions. The gyrfalcon migrates from the Arctic to occasionally spend the winter
in Alberta. Merlins overwinter in Edmonton and perhaps in other centres. Goshawks often spend the winter in the parkland
Updated: Aug 30, 2018