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Species of Special Concern
Status
Alaska species of special concern; Federal Sensitive Species
Description
The Queen Charlotte Goshawk is an uncommon, secretive, forest-dwelling raptor. It is the largest of the North American accipiter family, which also includes the Cooper's hawk and sharp-shinned hawk. Ornithologists currently recognize three subspecies of northern goshawks (Accipiter gentilis) in North America. The Queen Charlotte Goshawk (A. g. laingi) is the smallest and darkest of the three subspecies and occurs at low densities throughout the temperate rainforests of Southeast Alaska and coastal British Columbia.
Goshawks are large hawks (22-26 inches in length) and have long, broad wings and long, rounded tails, which afford them the great maneuverability necessary for navigating and capturing prey in dense forested environments. Like many birds of prey, goshawks are sexually dimorphic, with the female being larger in size than the male.
Adult birds are brown-gray to dark, slate gray or black on the back, and they are light gray with fine black horizontal barring and fine black vertical streaks on the breast and belly. The head has a dark black cap with a narrow white stripe above the eye. In adults, eye color ranges from mahogany to brilliant ruby-red depending on age and sex. Juveniles (less than one year old) are dark chocolate brown on the back and light tawny brown on the breast and belly with wide dark brown vertical streaks. The head is light brown with dark streaks on the crown and sides. Although the white eye stripe is also present on juveniles, it is less prominent than in the adults. Eye color in juveniles ranges from pale gray to bright yellow. The feet, cere, toes, legs and mouth lining range from a pale gray in juveniles to bright yellow in adults.
While goshawks are a rather silent species most of the year, they can produce a wide range of vocalizations, especially during the reproductive period. Two calls in particular are most likely to be detected by humans. The alarm call, a series of rapidly repeated cries resembling “kak-kak-kak-kak,” is most often used to protest the presence of intruders near the nest. The juvenile food-begging call, a loud “kree-ya,” is repeated at irregular and infrequent intervals and is similar to the cry of a gull.
Habitats and Habits
Goshawks inhabit a variety of habitat types in North America, ranging from open sage steppes to dense deciduous and coniferous forests. Research by the Alaska Department of Fish and Game (ADF&G) revealed that goshawks have relatively large home ranges in Southeast Alaska. Although they utilize a wide range of habitat types for foraging and loafing, they nest exclusively in old growth and mature forests. For these reasons the goshawk is considered an indicator species for the health of old growth forest ecosystems.
The Queen Charlotte Goshawk is believed to be a non-migratory resident of Southeast Alaska. Following the nesting season, adult females sometimes travel long distances to winter-use areas separate from their breeding territories. Unlike adult males, which maintain loose, year-round associations with their breeding territories, adult females occasionally select new mates and move to different breeding territories.
In Southeast Alaska, adult goshawks begin frequenting nesting stands in February and early March in preparation for breeding. Pair bonding, courtship, and nest building activities take place during late March and early April. Unlike numerous other raptors that place their nests high in the tops of tall trees, goshawks build their nests well beneath the forest crown at the bottom edge of the canopy. In Southeast Alaska goshawks generally place their nests close to the trunk, on stout side limbs, in mature conifer trees. The nest itself is constructed of sticks and bark and measures approximately 3 feet across and from 1 to 2 feet deep, depending on whether or not the nest has been used in previous years.
Adult goshawks
are notoriously aggressive when defending nests and young from perceived intruders. They will scream,
dive-bomb, and occasionally strike people or animals that approach too close to the nest tree.
The female lays from 2-5 eggs that hatch after approximately 30-32 days of incubation. During the breeding season (March to September), the female generally defends the nest and young while the male traverses a large home range in search of prey. Nestlings fledge and leave the nest at 35-42 days-of-age with males tending to fledge earlier than females. During this post-fledging period (mid-July to early September) young goshawks remain in the general vicinity of nests where adults continue to provide them with food until the young develop the flight skills necessary to survive on their own. As soon as the young goshawks become successful at pursuing and capturing prey on their own (65-95 days-of-age), they disperse from the nest site (August to mid-September).
Goshawks prey on small and medium-sized birds and mammals. In Southeast Alaska, goshawks are known to feed on jays, thrushes, crows, grouse, woodpeckers, waterfowl, squirrels and hares. Goshawks forage for prey either by flying rapidly along forest edges or by traveling through the forest in a series of short flights interrupted by brief periods of searching for prey from elevated hunting perches. Using these techniques, goshawks ambush their prey either in the air or on the ground.
Reasons for Concern
In Southeast Alaska, the loss of old growth and mature forest habitat to timber harvest is the primary threat to goshawk populations. Other human activities such as mining and urban development can also destroy goshawk nesting and foraging habitat.
Range of theQueen Charlotte GoshawkResearch and Recovery
In response to concerns that timber harvests in Southeast Alaska might be negatively impacting goshawk populations, the ADF&G and USDA Forest Service entered into a cooperative study of goshawk ecology and habitat relationships on the Tongass National Forest. Since 1991, researchers have identified 50 goshawk nesting areas in Southeast Alaska. To date 87 goshawks have been captured and fitted with tiny radio-transmitters to determine the habitat associations and home range size of this wide-ranging raptor. This research continues and is intended to provide natural resource managers with the information necessary to maintain both viable natural resource based industries and healthy goshawk populations across the Tongass.
Text: Rich Lowell
For Additional Information
Please contact:
Doug Vincent-Lang
(907) 267-2339
