The Northern goshawk is a medium-large diurnal bird of prey that is often considered a "true hawk". It has relatively short, broad wings and a long tail, common to raptors that require maneuverability within forest habitats. It is blue-grey above or brownish-grey with dark barring or streaking over a grey or white base color below, but Asian subspecies in particular range from nearly white overall to nearly black above. The juvenile Northern goshawk is usually a solid to mildly streaky brown above, with many variations in underside color from nearly pure white to almost entirely overlaid with broad dark cinnamon-brown striping. Both juveniles and adults have a barred tail, with 3 to 5 dark brown or black bars. Adults always have a white eye stripe.
Northern goshawks have a large circumpolar distribution. They are found in Eurasia and North America. In Eurasia, they are found in most areas of Europe excluding Ireland and Iceland. In North America, these birds are most broadly found in the western United States, including Alaska, and western Canada. 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. A majority of Northern goshawks around the world remain sedentary throughout the year. Birds from colder regions migrate south for the winter. Northern goshawks inhabit both mixed and coniferous forests. In Eurasia, especially central Europe, they may live in fairly urbanized patchworks of small woods, shelter-belts, and copses and even use largely isolated trees in central parts of Eurasian cities.
Northern goshawks are partial migrants. Migrations generally occur between September and November in the fall and February to April in the spring. These birds are diurnal and are always found singly or in pairs. They are highly territorial and maintain their home ranges in display flights. Northern goshawks are powerful hunters and mainly use a perch-hunting style; this includes a series of quick flights low to the ground, interspersed with brief periods of scanning for unsuspecting prey from elevated perches (short duration sit-and-wait predatory movements). More periodically, Northern goshawks may watch for prey from a high soar or gliding flight above the canopy. These graceful hunters are capable of considerable, sustained, horizontal speed in pursuit of prey which may achieve 38 mph (61 km/h). When gliding down from a perch to capture prey, a goshawk may not even beat its wings which makes its flight nearly silent. Northern goshawks often leave larger portions of their prey uneaten and sometimes cache prey on tree branches or wedged in a crotch between branches. These birds usually only vocalize during courtship or the nesting season. When calling from a perch, birds often turn their heads slowly from side to side, producing a ventriloquial effect. The male calls a fast, high-pitched 'kew-kew-kew' when delivering food or else a very different croaking 'guck' or 'chup'. Meanwhile, the adult female's rapid 'kek-kek-kek' expresses alarm or intent to mob towards threatening intruders. Occasionally hunting goshawks may make shrill screams when pursuing prey, especially during a lengthy chase and the prey is already aware of its intended predator.
Northern goshawks are carnivores and the most important prey species include small to medium-sized mammals and medium to large-sized birds found in forest, edge and scrub habitats. They will also hunt reptiles and amphibians, fish and insects.
Northern goshawks are monogamous and mate for life. They breed in April-July and during this time perform spectacular courtship flights on sunny days. The nest is placed in a tall tree under the canopy or near the main fork of a tree; it may be lined with hard pieces of bark and also with green sprigs of conifers. The female lays 2 to 4 rough, unmarked pale bluish or dirty white eggs. The incubation period lasts between 28 and 37 days and is done mainly by the female. The chicks hatch altricial; they are covered with down and measure about 13 cm. After hatching, the male does not come directly to the nest but instead just delivers food to a branch near the nest which the female tears apart and shares between herself and the nestlings. The mother typically broods the nestlings intensively for about 2 weeks, around the time grayer feathers start to develop through their down. The most key time for development may be at 3 weeks when the nestlings can stand a bit and start to develop their flight feathers. At 6 weeks of age, the chicks become "branchers", although still spend much of the time by the nest, especially by the edge. They rarely return to the nest after being 35 to 46 days of age and start their first flight another 10 days later, thus becoming full fledglings. Between 65 and 90 days after hatching, young goshawks become independent. They usually reach reproductive maturity at 2 to 3 years of age.
In many parts of the range, especially Europe, historic populations of Northern goshawks decreased regionally due to human persecution (especially shooting), disturbance and epidemic loss of habitat, especially during the 19th century and early 20th. Later, populations of this species declined from pesticides and heavy metals. Northern goshawks continue to be persecuted in some areas and suffer from deforestation of their habitat. Timber harvests destroy many nests and other noisy activities, such as camping, also cause nests to fail.
According to the IUCN Red List, the total Northern goshawk population size is around 1,000,000-2,499,999 mature individuals. The European population consists of 166,000-220,000 pairs, which equates to 332,000-440,000 mature individuals. According to the European Raptors Biology and Conservation resource, specific populations of the species have been estimated in such areas: 90,000 - 110,000 pairs in Russia; 12,900 - 13,900 pairs in Germany; 6,000 - 8,000 pairs in Sweden; 5,000 - 7,000 pairs in Romania; 4,600 - 6.500 pairs in France; 3,500 - 6,500 pairs in Spain. In total European population is around 180,000 pairs. Overall, currently, Northern goshawks are classified as Least Concern (LC) on the IUCN Red List.
Northern goshawks are important predators in the ecosystem they live in. These powerful hunters control populations of their main prey items such as small mammals and birds.