Coopers Hawk (Accipiter cooperii)

Coopers Hawk

[order] ACCIPITRIFORMES | [family] Accipitridae | [latin] Accipiter cooperii | [authority] Bonaparte, 1828 | [UK] Coopers Hawk | [FR] Epervier de Cooper | [DE] Rundschwanz-Sperber | [ES] Gavilan de Cooper | [NL] Coopers Sperwer

Subspecies

Genus Species subspecies Region Range
Accipiter cooperii NA, MA s Canada to Honduras

Genus

Members of the genus Accipiter are small and medium-sized hawks, often called Sparrow-hawks or Goshawks. The females are almost invariably much larger than the males – in some cases weighing twice as much – a level of size dimorphism only exceptionally reached in any other genus Falconiformes. Their wings are short and rounded; the tail usually quite long. They are well adapted for flying through dense bush. Bird-catching Sparrow-hawks generally have long and slender legs, with slender digits, the middle one being especially long. Goshawks are usually larger, with shorter, thicker tarsi and digits and a shorter middle digit. Some smaller species have goshawk-like feet and vice versa, making it difficult on a world-wide basis to subdivide the genus on this or any other broad basis. Although many accipiters feed upon birds moreso than do other hawks, some species take many mammals, especially squirrels; others take lizards, frogs, snakes, insects, even snails. In these species the legs and digits are sometimes slender, but short. Accipiters are rarely crested, but some have very attractive colour patterns. Black phases are present, especially in the tropical species. One in Australia has the only pure white phase. Accipiter is the largest genus in the family, having about fifty species. It is present worldwide, but is especially rich in Papua-New Guinea, where a small island like New Britain may have three to five endemic species or distinct sub-species.

Physical charateristics

A short-winged, long-tailed hawk, very similar to Sharp-shinned Hawk but larger; female usually is not quite as long as a Crow. The tail of female is well rounded, even
when folded; male’s less so. When the bird is gliding the head projects well beyond the wrists of the wing. The immature is brown, streaked on breast, white on belly. No strong white eye stripe as in the Goshawk.

Listen to the sound of Coopers Hawk

[audio:http://www.planetofbirds.com/MASTER/ACCIPITRIFORMES/Accipitridae/sounds/Coopers Hawk.mp3]

Copyright remark: Most sounds derived from xeno-canto


wingspan min.: 70 cm wingspan max.: 85 cm
size min.: 37 cm size max.: 39 cm
incubation min.: 30 days incubation max.: 36 days
fledging min.: 27 days fledging max.: 34 days
broods: 1   eggs min.: 2  
      eggs max.: 6  

Range

North America, Middle America : South Canada to Honduras

Habitat

Mature forest, open woodlands, wood edges, river groves.
Nests in coniferous, deciduous, and mixed woods, typically those with tall trees and with openings or edge habitat nearby. Also found among trees along rivers through open country, and increasingly in suburbs and cities where some tall trees exist for ne
st sites. In winter may be in fairly open country, especially in West.

Reproduction

The male selects the nest site and does most of the building. When a last year’s nest is used the female selects and repairs it. The male snaps off twigs for the nest by seizing them in his feet and using his weight. Smaller twigs may be carried in the bill. The pair roost not far away and at daybreak, about 5.30, begin a `duet’, the male first, uttering a great variety of notes. About 6.30 or 7.00 the male begins building and may bring a stick every few minutes and waste no time working it into the nest. He flies low through the woods, and shoots up almost vertically to the nest. Leaving, he dives down the same way, dropping his legs for a moment as he levels off. The female perches nearby and several times during the morning the male flies to her and mates. In mid-afternoon the male goes hunting; the female may also, but receives most of her food from the male. After he returns there is usually no further nest-building for the day. Nests of pairs are normally not closer than a mile-and-a-half of each other; nor do Sharp-shinned Hawks nest within the same distance. It takes two weeks to build ; little or no work is done on stormy days. However, if a clutch is lost another nest may be built in as little as four days.
A day or two before laying the nest is lined with flakes of hemlock, oak, or maple bark. The male may pounce on a piece of bark and tear it off as though catching prey; the female, if she participates, usually breaks off the bark with her bill. Bark is added during the incubation period and by the time the young hatch may be three inches deep. The male also adds an occasional green spray. When the young are two weeks old the nest gets crowded and the female adds a few sticks each day. At this time the male comes to the nest only to bring food (though usually intercepted by the female).
The eggs (normally four or five) are laid one every other day; or there may be two days between the fourth and fifth, if a fifth is laid. The eggs are usually laid early in the morning, the female remaining at the nest ten to twenty minutes for this purpose. Mating continues through nest-building and egg-laying; then ceases.
Incubation starts with laying of the third egg and is almost entirely by the female, but the male may take over briefly while the female is eating food he has brought; this may take fifteen to 30 minutes. The first three eggs pip after 34 days. Next day the holes are slightly larger, and on the 36th day these hatch and the fourth is pipped. On the following day the fifth egg is pipped and the fourth hatches. Hence the normal incubation period is 36 days, but if there is a fifth egg it usually only takes 35 days.
After incubation starts, the male continues on his usual roost nearby. When the male begins dawn `singing’ the female flies over and participates for ten or fifteen minutes, but returns before he finishes. By the third week the female leaves the nest only to take food from the male or to defecate. The male gradually ceases dawn chorus. The female interrupts incubation to turn the eggs or to preen every hour or so. The male brings food three or four times a day. When incubating as his mate eats, the male does so half heartedly and leaves the nest the second she reaches it on her return. If the eggs, when fresh or nearly so, are destroyed, another clutch will be laid ten or twelve days later in a hastily built nest not far away, or perhaps in the same nest if it is undisturbed except for the removal of the eggs.
The female is very attentive at hatching and will even help the young out of the eggs. The shells are carried 50 yards or more away and dropped, but if an egg does not hatch it is left in the nest indefinitely. When the young are small the female often preens at the edge of the nest, feeds the young and shields them from rain and sun. Sometimes the female rearranges the material in the lining of the nest while the young crowd to one edge; she may carry off a bone or pellet. The female sleeps on the nest till the young are two weeks old. The female discontinues this practice only when there is no longer room for her in the nest; she may then perch a few feet away for a night or two before selecting a perch within 50 feet of the nest. The male never sits on the nest after the young hatch, but will carry off a piece of shell if a young hatches while he is sitting. During the first three weeks the female is very attentive and the male is seldom allowed to bring food to the nest; she meets him. After three weeks the female is often absent; the male then takes food to the nest; he removes refuse, but only very exceptionally feeds the young, and then perhaps only when the female is there.
After the young leave the nest, the male will bring prey to the nest and wait for the young to come piling back for it; or go and look for them and often fly ahead of them back to the nest and drop the prey there. Later the young meet the male coming with prey and buffet him so that it is dropped and they eat it on any convenient log or old nest. Usually the male eats the head and viscera of prey before bringing it to his mate or young. The prey is then taken to a plucking stump, usually within a hundred yards of the nest. Actually most of the plucking is done where the prey is caught and only the finishing touches at the plucking stump. At the latter he plucks, then calls `kik’, the female soon answers `whar’ and flies for the prey. At the moment it is passed over both birds shriek. The female continues the plucking as she flies to the nest. It takes her ten to thirty minutes to feed the young, which gather in a semi-circle. The female now and then swallows a wing or large bone herself. When only a skeleton remains she carries it to a perch to finish. Sometimes the female sees her mate approaching with prey and pursues him. He drops the booty which she picks up from the ground. If the male brings more food than is needed it is placed on an old nest nearby and used as appetite dictates. If the female, later in the cycle, should not come to the plucking stump for the prey the male peers and whines impatiently; then carries the food to the nest. The male, which brought prey to the incubating female only two or three times a day, has to hunt constantly when the young are large; and plucks the prey less thoroughly and does not decapitate it. The young, eating this roughage, begin to cast a pellet each day, usually about 6 a.m.
The young grow very rapidly for the first seventeen days; then slow down abruptly before feathering out and continue to grow slowly for about three weeks until feathered out and full grown. At the age of three weeks a female nestling can stand and feed herself. One of the smaller and more agile males may move next to her and snatch every piece of meat she tears off, as though he were taking it from the adult female. From this age on they become very active. The males usually leave the nest at 30 days, the females at 34. Food may be brought to the nest for ten days thereafter and the young at first return to sleep or rest also. They will also sprawl out sunning on the nest. If they see running water they will fly down to it and bathe.
The young are silent until they leave the nest, but after they scatter they utter loud and persistent hunger calls : `tsee-ar’. It takes them some three weeks to learn to hunt; they slowly start to hunt for themselves at about eight weeks old. During this time they are dependent upon their parents for food. At this age the parents are losing interest; one may carry prey to a tree near the begging young, eat part of it and leave the rest for the young. Adult cackling notes were first heard when one was about seven weeks old.

Feeding habits

Mostly birds and small mammals. Feeds mainly on medium-sized birds, in the size range of robins, jays, flickers; also on larger and smaller birds
. Also eats many small mammals, such as chipmunks, tree squirrels, ground squirrels, mice, bats. Sometimes eats reptiles, insects.
Behavior:
Usually hunts by stealth, moving from perch to perch in dense cover, listening and watching, then putting on a burst of speed to overtake prey. Sometimes cruises low over ground, approaching from behind shrubbery to take prey by surprise.
In hunting the hawk flies to an inconspicuous perch and carefully looks about for prey. If it sees a chipmunk or red squirrel it will wait until it is sufficiently far from cover and looking the other way, then leave its perch and with a sudden burst of speed usually seize the victim before it is alarmed. If, when flying, the hawk sees birds, for example starlings or robins feeding on the ground near cover, it does not approach directly, but circles around taking advantage of trees and bushes and alights where it can size up the situation. At the proper moment it leaves the perch and flies low, taking advantage of every bush and dip in the ground. If the birds see it and flee it flies a little higher to increase its chances of catching one. When the young hawks are learning to hunt, two may pursue the same squirrel which is caught by one as it seeks to dodge the other by dashing around a tree trunk. This is not really co-operation, but the results are the same. Many birds are caught by pursuit as they fly near a tree in which the hawk is perched. If prey is not caught within a hundred yards the chase is given up. When attracted by bats swarming out of caves it singles one out, follows every twist and turn, and seizes its prey solidly, succeeding in 90% of attempts.

Video Coopers Hawk

httpv://www.youtube.com/watch?v=nt_cgLOx8ZQ

copyright: D. DesJardin


Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Coopers Hawk status Least Concern

Migration

Generally migratory from North half of range, but some birds remain even at North part of range. Sedentary elsewhere, though birds at high altitudes may move to lowlands. In autumn, yearlings migrate first, and females precede males in each age category; migration late August-early November, with peak from mid-September to mid-October. In spring, males precede females, March-May. Migrates commonly to Mexico, but as far as Costa Rica and rarely Colombia.

Distribution map

Coopers Hawk distribution range map

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