Black sparrowhawk

Appearance

Typically, both sexes of the black sparrowhawk have a predominantly black plumage with a white throat, breast and belly. These white-breasted individuals are known as "white morphs" which are in the majority over most of the birds' range.

There is no noticeable difference between the plumage of mature females and males, which can only be distinguished by size. The tails are cross-barred with about three or four paler stripes, and the undersides of the wings with perhaps four or five. The legs are yellow, with large feet and talons.

Young chicks have mid-grey eyes and white down, but when the feathers erupt they are predominantly brown. The full plumage of juveniles is a range of browns and russets with dark streaks along the head and, more conspicuously, down the chest.

Commonly there are white or light-colored spots and streaks as well, mainly on the wings. The brown plumage being a sign of immaturity, it does not attract as dangerously aggressively territorial behavior as a mature black-and-white bird would. As the young birds mature, their eyes change in color from mid-grey, through light brown, to dark red.

Distribution

Black sparrowhawks are relatively widespread and common in sub-Saharan Africa and listed as not globally threatened by CITES. Densities range from one pair per 13 square kilometers in Kenya to one pair per 38-150 square kilometers in South Africa. On the Cape Peninsula, however, in the southwestern corner of South Africa, the nest are typically only 500 m apart in the pine plantations and other continuous or semi-continuous belts of trees.

Reproduction

"A. m. temminckii" usually breed between August and November while "A. m. melanoleucus" breed between May and October. In Zambia, they breed at an intermediate time, between July and February. Black sparrowhawks in eastern Africa seemingly breed at almost any time of the year. These birds are particular about their nest sites; they prefer sites within the tree canopy to protect their offspring from adverse weather conditions and other predators. Nests have been found from 7 to 36 m high in trees, though have been found on the ground between large tree trunks. However, the nests are usually not deep within the forest in order to stay within close proximity of the hunting habitat outside of the forest.

The nests are made up of thousands of sticks collected by both parents and are usually lined with green eucalyptus leaves, pine needles, camphor leaves or other aromatic greenery possibly to deter carriers of diseases, such as mites and insects, due to the repelling smell of the leaves, though greenery is often put in place weeks before the first egg is laid. The nests can measure from 50 to 70 cm in width and 30–75 cm deep.

Black sparrowhawks form monogamous pairs, though extra-pair matings are not uncommon. A nesting pair will mate regularly throughout the breeding season, starting during courtship and continuing till after the chicks have fledged.

Once nest building or refurbishing starts the female becomes lethargic, and the male does nearly all the hunting and provisioning of the female and the chicks when they hatch. Typically, the female will lay 2-4 eggs and the pair will incubate them for about 34–38 days until they hatch. Most of the incubating is done by the female, but the male will take over after he has brought in prey.

The female will then eat the food, and possibly bathe in a nearby stream, before taking over the incubation once again. This behavior persists into the brooding period, with intense brooding by the female lasting up to 21 days after which the female may also start to hunt for food, but only if the nest is left largely undisturbed by other predators. She remains the chief defender of the nest and the chicks. The newly hatched chicks are semialtricial in that they are fully covered in white down feathers but cannot leave the nest since they rely on the parents for food, warmth, and protection. After 37 to 50 days, the juveniles are fledged but the parents will continue to care for them for the next 37 to 47 days. The entire time from egg-laying to the juvenile independence can, therefore, be 20 weeks, or 5 months.

Black sparrowhawks are known to attempt multiple brooding on occasions. This behavior is exceeding rare in birds of prey. The second brood may be raised in the same nest, or in a second nest nearby, where the fledglings from the first brood will continue to be fed by the parents. In the Cape Peninsula, South Africa, they are also known to build multiple nests in a season, and this behaviour is thought to be an adaptation to dealing with usurpation by Egyptian Geese.

Nests are usually re-used year after year, frequently by the same pair. One nest is, in fact, known to have been used continuously for 32 years by a succession of pairs.

Food

Black sparrowhawks prey primarily on mid-sized birds. Most prey is spotted from a foliage-concealed perch, which is then killed in flight during a short flying dash.