The American goshawk (Astur atricapillus) is a species of raptor in the family Accipitridae. It was first described by Alexander Wilson in 1812. The American goshawk was previously considered conspecific with the Eurasian goshawk but was assigned to a separate species in 2023 based on differences in morphology, vocalizations, and genetic divergence. It was formerly placed in the genus Accipiter. It is mainly resident, but birds from colder regions migrate south for the winter. In North America, migratory goshawks are often seen migrating south along mountain ridge tops at nearly any time of the fall depending on latitude.
Distribution In North America, they are most broadly found in the Western United States, including Alaska, and western Canada. Their breeding range in the western contiguous United States largely consists of the wooded foothills of the Rocky Mountains and many other large mountain ranges from Washington to southern California extending east to central Colorado and westernmost Texas. Somewhat discontinuous breeding populations are found in southeastern Arizona and southwestern New Mexico, thence also somewhat spottily into western Mexico down through Sonora and Chihuahua along the Sierra Madre Occidental as far as Jalisco and Guerrero, their worldwide southern limit as a breeding species.Monson, G. & Phillips, A. R. (1964). A check-list of the birds of Arizona. Tucson: Univ. of Arizona Press.Howell, S. N. G. & Webb, S. (1995). A guide to the birds of Mexico and northern Central America. New York: Oxford University Press.
The goshawk continues east through much of Canada as a native species, but is rarer in most of the Eastern United States, especially the Midwest, where they are not typically found outside the Great Lakes region, where a good-sized breeding population occurs in the northern parts of Minnesota, Illinois, Michigan, and somewhat into Ohio; a very small population persists in the extreme northeast corner of North Dakota. They breed also in mountainous areas of New England, New York, central Pennsylvania, and northwestern New Jersey, sporadically down to extreme northwestern Maryland and northeastern West Virginia. Vagrants have been reported in most of the parts of the United States in which they do not breed.
Habitat
American and Eurasian goshawks can be found in both deciduous and coniferous forests. While the species might show strong regional preferences for certain trees, they seem to have no strong overall preferences nor even a preference between deciduous or coniferous trees despite claims to the contrary. More important than the type of trees are the composition of a given tree stand, which should be tall, old-growth with intermediate to heavy canopy coverage (often more than 40%) and minimal density undergrowth, both of which are favorable for hunting conditions. Also, goshawks typically require proximity to openings in which to execute additional hunting.Erickson, M. G. (1987). Nest site habitat selection of the goshawk (Accipiter gentilis) in the Black Hills of South Dakota (Doctoral dissertation, MS thesis. University of South Dakota. Brookings, South Dakota).
Access to waterways and riparian zones of any kind is not uncommon in goshawk home ranges but seems to not be a requirement. Narrow tree-lined riparian zones in otherwise relatively open habitats can provide suitable wintering habitat in the absence of more extensive woodlands. The American goshawk can be found at almost any altitude, but recently is typically found at high elevations due to a paucity of extensive forests remaining in lowlands across much of its range. Altitudinally, goshawks may live anywhere up to a given mountain range's tree line, which is usually in elevation or less. In winter months, the northernmost or high mountain populations move down to warmer forests with lower elevations, often continuing to avoid detection except while migrating. A majority of goshawks around the world remain sedentary throughout the year.
Description Similar species
The juvenile plumage of the species may cause some confusion, especially with other juvenile Astur species. Unlike other northern Astur, the adult American and Eurasian goshawk never has a rusty color to its underside barring. Wing beats of American goshawks are deeper, more deliberate, and on average slower than those of the two other North American Asturs.Cramp, S. and K. E. L. Simmons. (1980). Handbook of the birds of Europe and the Middle East and North Africa: the birds of the western Palearctic, Vol. 2. Hawks to bustards. Oxford: Oxford Univ. Press. Kaufman, K. (1990). A Field Guide to advanced birding: birding challenges and how to approach them. Boston, MA: Houghton Mifflin Co.
American goshawks are sometimes mistaken for species even outside of the genus Astur especially as juveniles of each respective species. In North America, four species of buteonine hawk (all four of which are smaller than goshawks to a certain degree) may be confused with them on occasion despite the differing proportions of these hawks, which all have longer wings and shorter tails relative to their size. A species so similar it is sometimes nicknamed the "Mexican goshawk", gray hawk (Buteo plagiatus) juveniles (overlapping with true goshawks in the southwest United States into Mexico) have contrasting face pattern with bold dusky eye-stripes, dark eyes, barred thighs and a bold white "U" on the uppertail coverts. The roadside hawk (Rupornis magnirostris) (rarely in same range in Mexico) is noticeably smaller with paddle-shaped wings, barred lower breast and a buff "U" on undertail coverts in young birds. Somewhat less likely to confuse despite their broader extent of overlap are the red-shouldered hawk (Buteo lineatus) which have a narrow white-barred, dark-looking tail, bold white crescents on their primaries and dark wing edges and the broad-winged hawk (Buteo playpterus) which also has dark wing edges and a differing tapered wing shape. Even wintering gyrfalcon (Falco rusticolus) juveniles have been mistaken for goshawks and vice versa on occasion, especially when observed distantly perched. However, the bulkier, broader headed yet relatively shorter tailed falcon still has many tell-tale falcon characteristics like pointed, longer wings, a brown malar stripe as well as its more extensive barring both above and below.
Juveniles are sometimes confused with the smaller Cooper's hawk (Astur cooperii), especially juvenile Cooper's hawks. Unlike in Europe with sparrowhawks, Cooper's hawks can have a largish appearance and juveniles may be regularly mistaken for the usually less locally numerous goshawk. However, the juvenile goshawk displays a heavier, vertical streaking pattern on chest and abdomen, with the juvenile Cooper's hawk streaking frequently (but not always) in a "teardrop" pattern wherein the streaking appears to taper at the top, as opposed to the more even streaking of the goshawk. The goshawk sometimes seems to have a shorter tail relative to its much broader body. Although there appears to be a size overlap between small male goshawks and large female Cooper's hawks, morphometric measurements (wing and tail length) of both species demonstrate no such overlap, although weight overlap can rarely occur due to variation in seasonal condition and food intake at time of weighing..
Taxonomy The genus Astur contains nine living species. This group of agile, smallish, forest-dwelling hawks has been in existence for possibly tens of millions of years, probably as an adaptation to the explosive numbers of small birds that began to occupy the world's forest in the last few eras. The harriers are the only group of extant diurnal raptors that seem to bear remotely close relation to this genus, whereas buteonines, Old World kites, sea eagles and chanting-goshawks are much more distantly related and all other modern accipitrids are not directly related.
Within the genus Astur, the American goshawk seems to belong to a superspecies with other larger goshawks from different portions of the world.Kleinschmidt, O. (1923). Berajah, Zoografia infinita. Die Realgattung Habicht, Falco columbarius (KL). Gebauer-Schwetschke, Halle, Germany. Eurasian goshawk, found in Eurasia, was previously considered conspecific with American goshawk, formed the species complex "northern goshawk". Meyer's goshawk, found in the South Pacific, has been posited as the most likely to be the closest related living cousin to the northern goshawk, the somewhat puzzling gap in their respective ranges explained by other Palearctic raptors such as Bonelli's eagles (Aquila fasciata) and short-toed eagles (Circaetus gallicus) that have extant isolated tropical island populations and were probably part of the same southwest Pacific radiation that led to the Meyer's goshawk.. A presumably older radiation of this group may have occurred in Africa, where it led to both the Henst's goshawk of Madagascar and the black sparrowhawk (Astur melanoleucus) of the mainland. While the Henst's goshawk quite resembles the northern goshawks, the black sparrowhawk is superficially described as a "sparrowhawk" due to its relatively much longer and finer legs than those of typical goshawks but overall its size and plumage (especially that of juveniles) is much more goshawk than sparrowhawk-like.
Genetic studies have indicated that the Cooper's hawk of North America is also fairly closely related to the northern goshawk, having been present in North America before either of the two North American species of Astur. However, the much smaller sharp-shinned hawk, which has similar plumage to the Cooper's hawk and seems to be most closely related to the Eurasian sparrowhawk, appears to have occupied North America the latest of the three North American species of Accipitrinae, despite having the broadest current distribution of any of the American members of Accipitrinae (extending down through much of South America).
Subspecies