Palearctic, Nearctic: The Northern Goshawk Accipiter gentilis is widely found throughout the mountains and forests of North America and Eurasia.

Physical Characteristics

Mass: 816 to 1059 g.

The Northern Goshawk is the largest example of the Accipiter genus. On average, the males weigh 816 grams (1.8 pounds) and have a wingspan of 101 centimeters (39.4 inches). Females are slightly larger, weighing an average of 1059 grams (2.3 pounds) and having an average wingspan of 108 centimeters (42.1 inches).

All Accipiters, including the Northern Goshawk, have a distinctive white grouping of feathers which form a band above the eye (superciliary). In the Goshawk this band is thick and more pronounced than the other members of the species. The adult Goshawks' eye color is red to reddish-brown and the juveniles' eyes are bright yellow.

The colorings of an adult male and female Northern Goshawk range from slate blue-gray to black. Their backs, wing tops and heads are usually dark and their undersides are white with fine gray horizontal barring. Their tails are light gray with three or four dark bands.

A juvenile Northern Goshawk's coloring is quite different than that of the adult. Their backs, wing tops and heads are brown and their undersides are white with vertical brown streaking

Food Habits

The Northern Goshawk is carnivorous and consumes birds, mammals, invertebrates and reptiles of moderate to large size with prey weighing up to one-half as much as itself. The content of an individual Goshawks diet depends upon the environment in which that Goshawk lives and the hawk's preference. Their average diet consists of 21 to 59 percent mammals, 18 to 69 percent birds with the remaining percentages being made up of reptiles and invertebrates.

Reproduction

A mating pair of Northern Goshawk begins to prepare their nest as early as two months before egg laying. Typically, the nest is located in an old growth forest, near the trunk of a medium to large tree and near openings in the forest such as roads, swamps and meadows. Their nest are usually about one meter (39.4 inches) in diameter and one-half to one meter (19.7 to 39.4 inches) in height and are made of dead twigs, lined with leafy green twigs or bunches of conifer needles and pieces of bark.

The typical clutch size is two to three eggs, which are laid in two to three day intervals. The eggs are rough textured, bluish-white in color and measure 59x45 millimeters (2.3 x 1.8 inches) in size. The clutch begins to hatch within 36 to 41 days of laying. Incubation of the eggs is primarily the female's job, but occasionally the male will take her place to allow the female to hunt and eat.

After the clutch has hatched, the female will not leave the nesting area until the nestlings are 25 days old. During this time the male is the primary provider of food for the female and her nestlings. When the nestlings reach 25 days the female will leave them and hunt with the male (Johnsgard 1990; Baicich et al. 1997).

Behavior

When the nestling Goshawk reaches 35 to 42 days old, he will begin to move to the nearby branches of the tree. Soon after this practice flights begin to occur. Often the fledglings participate in "play" which is thought to allow them to practice hunting skills which will be needed throuout their lives. The young Goshawks do not become fully independent of their parents until they are 70 to 80 days old.

Most Goshawk populations are sedentary and they typically remain in their nesting areas throughout their lives. Only the Goshawks that breed in the north and northwestern parts of North America are migratory. They fly south during the winter months and then return to their nesting areas in the spring.

Male and female Goshawks typically maintain a life-long pair bond and only upon death will they seek out a new mate. Goshawks are highly territorial and a mating pair will advertise their nesting territory by performing an elaborate aerial display before and during nest construction and/or repair. If their nesting area is encroached upon, they will defend it fiercely.

When courting a mate, the female Goshawk will attract males in the area by either performing dramatic "Sky Dances" and calling out, or by perching in the nesting area and calling out. Once a mate has been found, the two Goshawks begin to construct/repair their nest. During this time the pair will copulate many times a day.

Habitat

Northern Goshawks can be found in coniferous and deciduous forests. During their nesting period, they prefer their habitats to be a mature forest consisting of a combination of old, tall trees with intermediate canopy coverage and small open areas within the forest for foraging. During the cold winter months they will vertically migrate down into the warmer foothill areas or the savannas.