Accipiters are hawks characterized by long tails and short, broad wings. They are the "true" hawks in that accipiter is Latin for "bird of prey". However, the original derivation of the word is thought to be from the Greek aci ("swift") and pteron ("wing"), referring to the speed and agility of these birds. The sharp-shinned hawk is named after a prominent ridge on its tarsi (despite the tarsus being analogous to the arch of the human foot rather than the shin). Its scientific name, Accipiter striatus, refers to the heavily streaked underparts of the juvenile, which was described before the adult. The Cooper’s hawk, Accipiter cooperii, was named in honour of New York ornithologist William Cooper. The northern goshawk derives its English name from the Anglo-Saxon gos and havoc, meaning a hawk which hunts geese. Its scientific name is Accipiter gentilis, meaning "noble hawk", a reference to the fact that only those of an elevated social stature were permitted to use this bird for falconry in mediaeval times.

Identification:
As is the case with many raptors, plumage differences between the sexes are minor at best among accipiters, however, females are significantly larger than males. All immature accipiters are brown on the back and have whitish underparts streaked with brown. Adults are slate blue-gray above and heavily barred with rufous (sharp-shinned and Cooper’s) or gray (goshawk) below.

Distribution:
All three accipiters are distributed quite widely across North America. The sharp-shinned hawk has the greatest range, breeding across Canada and many northern states, and wintering from southern Canada through Panama. The Cooper’s hawk is more southerly, breeding regularly in all of the continental states except North Dakota, and along the southern edges of most provinces; only individuals from the northern edge of the breeding range tend to be migratory. The goshawk has the most northern distribution, breeding across Canada, as well as through much of the Rockies and northern Appalachians. Goshawks are not strongly migratory, but will periodically winter as far south as northern Mexico when there is a shortage of prey on their breeding grounds.

Natural history:
All of the accipiters prey primarily on smaller birds, though the Cooper’s will also take some small mammals and herptiles on occasion, and the goshawk hunts medium-sized mammals (e.g hares) quite regularly. The typical hunting strategy is to wait silently on an inconspicuous perch until prey comes near, then attack with a rapid burst of flight. The goshawk, and to a lesser extent the Cooper’s hawk, will also actively search for prey by flying relatively close to the ground and trying to use the element of surprise to their advantage. Both species will occasionally chase their quarry on foot if the vegetation is too thick to allow pursuit by flight.

Accipiters tend to nest in medium to large forests, and in general show a preference for areas relatively undisturbed by human activity. They may use either existing nests (often those of crows), or construct their own out of sticks, strips of bark, grasses, and feathers. Nests are normally situated near the trunk of a tree; the sharp-shinned and goshawk prefer conifers, while the Cooper’s is less particular. Courtship generally takes place relatively near the nest, and may involve a variety of aerial dives and swoops, performed alone or as a pair. Though rarely heard through the rest of the year, accipiters can be quite vocal during courtship. All three species give a variation of a call consisting of sharp "kak" notes. Once nesting has begun, accipiters tend to be very shy and reclusive. Even when an active terrritory is discovered, it can be difficult to pinpoint the actual nest. All accipiters are very protective of their territories, but none more than the goshawk, which is absolutely fearless and does not hesitate to strike any intruders, including humans.

The eggs of accipiters are off-white, usually with a faint bluish or greenish tinge and spotted or lightly streaked with brown. Those of the sharp-shinned and Cooper’s hawks average 39 mm (1.5") in length, while the goshawk’s eggs are 59 mm (2.3") long. Incubation requires 32 to 36 days for the smaller species, and 36 to 38 days for the goshawk. Fledging times are also related to the size of the species: 24 to 27 days for sharp-shinned, 27 to 34 days for Cooper’s, and 35 to 42 days for goshawks. Sharp-shinned hawks may be independent within less than a month of fledging, but juvenile Cooper’s and goshawks remain with their parents for four to six weeks. Like peregrines, accipiters acquire adult plumage toward the end of their second summer. Only a small fraction of accipiters breed before reaching full maturity, and as many as half of goshawks wait until their third year.

Though seldom seen by most people during the spring and summer because of their retiring habits, accipiters become quite conspicuous during the fall when sharp-shinned hawks in particular migrate south in large numbers. Those accipiters which remain in the north for the winter are frequently sighted, as they often stake out bird feeders for easy hunting. A backyard with an active feeder and nearby cover in the form of a dense bush or tree is ideal. Of the "backyard peregrines" reported to CPF, 95% or more are in fact accipiters, mostly Cooper’s hawks because of the close similarity in size. While the peregrine is a highly skilled hunter, it is adapted to aerial pursuits, and would actually have very little success if it attempted to hunt from a low perch in the manner of an accipiter.

Conservation:
The populations of all three accipiters decreased as a result of eggshell thinning due to DDT contamination in the 1960s and 1970s. The sharp-shinned and Cooper’s hawks were both placed on the National Audubon Society’s Blue List in 1972, indicating that they were in serious decline. However, accipiter populations have recovered well, and are currently stable or increasing over most of their range. The sharp-shinned hawk is the most common of the three accipiters, and is seen in large numbers each fall at raptor migration watches across North America. The Canadian population is estimated to be between 500,000 and 1,000,000 pairs, making it Canada’s most abundant raptor of any kind. The Cooper’s hawk remains less common (10,000 to 50,000 pairs in Canada), but is increasingly being found in some urban areas. The northern goshawk is the least frequently seen member of the genus, though this is largely because it frequents more remote areas; its Canadian population is also estimated to be 10,000 to 50,000 pairs.