The Cooper's Hawk is a crow-sized, very manoeuverable, forest hawk that occurs mainly in open mixed deciduous and coniferous forests. During migration it can occur in any relatively open treed area. Adults are dark gray above with a cinnamon chest and belly barred with fine lines of white. Adults also have black crowns (top of head) which are darker than the back color. That is, the dark cap contrasts with the pale nape and blue-gray dorsal area. The tail and wings are strongly barred, and the vent is pure white. The head is gray, the throat pale, and eyes red in full adults. In immatures, the eyes are gray to yellow. The beak is gray at the tip, and pale at the base with a yellow cere. The legs and feet are yellow. Colors of adult males are brighter than adult females. Immatures are brown above and vertically streaked with brown and white on the chest and belly; their wings and tails are barred, as with adults. In flight, Cooper's Hawks have short, rounded wings and a long round-tipped tail with a noticeable white terminal band. It soars and glides on level wings with wings held straight out from the body or in a slight dihedral.
It is a secretive, and often inconspicuous woodland hawk, especially during the breeding season. It breeds throughout most of southern Canada, the United States, and northern Mexico. It feeds mainly on medium-sized birds and mammals like jays and chipmunks.
The Cooper's Hawk is a common migrant at many eastern and western hawk watch locations.
SIZE
The Cooper's Hawk is strongly sexually dimorphic in size, with females being up to 50 percent larger than males. It is the medium-sized accipiter hawk, being about 50 percent larger than the Sharp-shinned Hawk but about half the size of the Northern Goshawk. Lengths average 18 inches (45 centimeters) for females and 15 inches (26 centimeters) for males. Wingspans average 33 inches (84 centimeters) for females and 29 inches (73 centimeters) for males. Weights average 19 ounces (530 grams) for females and 12 ounces (340 grams) for males. The largest females may reach weights of 1.5 pounds (675 grams).
MORPHS
There are no light or dark morphs phases for this species. Partial albinism is only known from British Columbia. A gray aberrant plumage has recently been described in California.
Specific Description
Adult - Perched
- dark gray (at times slate-blue) back and head; light gray nape
- head often squarish-looking because of raised hackles
- crown (top of head) much darker than nape and back
- long tail, strongly barred (black on gray), and usually rounded with three to four dark bands of equal width
- wide white tip on tail
- orange (young adults) to red (full adults) eye; yellow legs and feet
- cinnamon chest and belly finely barred with white
- males are brighter than females overall.
Immature - Perched
- brown back and top of wings
- squarish-looking head a very tawny to golden color
- strongly barred (brown on buff) tail that is very rounded at end
- three to four dark bands of equal width
- wide terminal tail band
- grayish or greenish eye, yellow legs and feet
- whitish underparts striped with lfine neat brown lines which are heaviest on breast and upper belly
- brownish immature plumage is replaced with the more colorful adult plumage during their second year.
SIMILAR SPECIES
The Cooper's Hawk is most often confused with the similar-looking Sharp-shinned Hawk. The Cooper's Hawk is much larger on average, but female (the larger sex) Sharp-shinned and male (the smaller sex) Cooper's Hawk can appear to be the same size although they never are. In flight, the Cooper's Hawk has a bulky-looking head and holds its wings straighter, whereas the Sharp-shinned Hawk has a small and narrow head and wings that jut forward at the wrist. The Cooper's Hawk usually has a rounded tail with a well-defined white terminal band, whereas the Sharp-shinned Hawk usually has a square-tipped tail with a thin white terminal band. Immature Cooper's Hawks appear light below whereas immature sharpies appear dark below. Finally, the Cooper's Hawk flaps its wings more deliberately than does the Sharp-shinned Hawk.
Immature Cooper's Hawks can also be confused at a distance with immature Northern Goshawks, which have similar plumage patterns. The immature Northern Goshwak has dark streaks on the under tail coverts while all immature Cooper's Hawks have white under tail coverts. The Cooper's Hawk underparts appear light whereas the Northern Goshawk underparts appear dirty or dark. Also, the immature Cooper's Hawk lacks the tawny bar on the wing coverts found in the immature Northern Goshawk. Northern Goshawks have deep, powerful wingbeats compared to the Cooper's Hawk more shallow and rapid wingbeat.
Small woodland buteos like the Broad-winged Hawk and Red-shouldered Hawk could be confused with the Cooper's Hawk because they occupy similar habitat and have a few similar features. However, they have broader wings and tail and fly much slower than the Cooper's Hawk.
OTHER NAMES
It has also been known as "chicken hawk", "big blue darter", and "quail hawk."
ETYMOLOGY
The scientific name Accipiter cooperii translates into "Cooper's bird of prey". William Cooper was a noted 19th century ornithologist.
MYTHOLOGY
None is reported.
VOICE
The Cooper's Hawk is usually silent except during the breeding season. Mates likely communicate mainly by calling because of the poor visibility in their woodland habitats. Females have up to 42 different calls and males up to 22 different calls. Female voices are lower and slower than males. During the nesting season, the loud alarm call "cak-cak-cak-cak..." is the most often heard call. Males give a "kik" call when returning to the nest with food, to announce his presence to the female, during courtship, and while nest-building. Females give the "kik" call when trying to locate the male, when flying towards the nest, or during nest-building. The females give a "whaaa" call during food exchanges with the male; when flying towards the male and expecting food; when plucking prey; and when flying to the nest with food. Both sexes give short "whaaa" calls during copulation. Nestlings chirp and cheep at one to two weeks of age, then whine when begging for food.
