| Black Sparrowhawk | |
|---|---|
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Falconiformes (or Accipitriformes, q.v.) |
| Family: | Accipitridae |
| Genus: | Accipiter |
| Species: | A. melanoleucus |
| Binomial name | |
| Accipiter melanoleucus Smith, 1830 |
|
The Black Sparrowhawk (Accipiter melanoleucus), sometimes known as the Black Goshawk or Great Sparrowhawk, is the largest African member of the genus Accipiter [2]. It occurs mainly in forests and non-desert areas south of the Sahara, particularly where there are large trees suitable for nesting; favoured habitat includes suburban and human-altered landscapes[2]. It preys primarily on birds of moderate size, such as pigeons and doves in suburban areas [3].
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Typically, both genders of the black sparrowhawk are pied black-and-white when mature; generally the plumage is predominantly black, but with a white chest and throat [4]. Some individuals may have a tendency towards melanism, showing white only on the throat and spots on the belly.[2][5][4] As a rule there is no noticeable difference between the plumage of mature females and males.[4] The tails are cross-barred with about three or four paler stripes, and the undersides of the wings with perhaps four or five, but these are less well-defined.
Young chicks have black 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-coloured spots and streaks as well, mainly on the wings.[2] The brown plumage being a sign of immaturity, it does not attract as dangerously aggressively territorial behaviour as the mature black-and-white would. As the young birds mature, their eyes change in colour from deep black, though brown, to red [2].
As is common in the genus Accipiter, male Black Sparrowhawks are smaller than females; typically the weights of males lie between 450g and 650g as compared to females, which have weights in the range 750g to 980g.[6]. The typical head-body length is 46 — 58 cm. The ceres and legs are yellow[5]. The wingspans are modest for such a large raptor, typically not more than 1 metre;[3] this probably reflects their arboreal habitat, though they also hunt very efficiently in open areas. The beaks and talons are typical of the genus Accipiter, and of raptors in general, being used both in capturing prey and in feeding.
There are 2 subspecies of the Black Sparrowhawks: Accipiter melanoleucus melanoleucus, which was named by A. Smith in 1830, and Accipiter melanoleucus temminckii, which was named by Hartlaub in 1855 [5]. As described in the next section, the 2 subspecies occur in different regions of Africa and both belong to the genus Accipiter in the Accipitridae family along with other well‐known members such as hawks and eagles, all of which are part of the Falconiformes order [7].
Black Sparrowhawks are relatively widespread and common in sub-Saharan Africa and listed as not globally threatened by CITES[5]. Densities range from one pair per 13 square kilometers in Kenya to one pair per 38-150 square kilometers in South Africa[5].
Both subspecies are only found in parts of Africa that are south of the Sahara desert; A. m. temminckii inhabit much of the northwest section such as Senegal, the Democratic Republic of the Congo, and Central African Republic, while A. m. melanoleucus can be found starting from the northeast section down to South Africa [2]. They mainly inhabit forest patches and favour large trees, including the non-indigenous eucalypt, poplar, and pine, all of which are grown commercially and are able to grow up to 15 m taller than native trees [6]. Their adaptability to secondary forests and cultivations is one of the reasons why they are not as greatly impacted by deforestation as many African forest birds[5].
In some areas such as Cape Peninsula, the sparrowhawks face habitat competition with Egyptian geese (Alopochen aegyptiaca), an aggressive species known to steal the nests of the sparrowhawks [3]. This results in a costly loss for the sparrowhawks after the time and energy spent building the nest and may also lead to the death of current offspring [3]. However, sparrowhawks are known to have more than 1 nest at a time, so in the event that one is usurped by an Egyptian goose, the pair would either inhabit the alternative nest and/or build a new one [3].
Black Sparrowhawks chase mid-sized birds through relatively open areas in Africa. They are not as nimble as smaller Accipiters, but their speed and short, broad wings facilitate the chase of birds well inside the forest.
Normally silent except during the breeding season[8]. Males are known to make loud “keeyp” sounds while females make short “kek” sounds [9].
Black Sparrowhawks prey primarily on birds in the size range of 80-300 g[5]. They often take doves and pigeons that have flourished due to urban growth and settlement [3]. It is one of the more fortunate species that have been able to adapt to their changing habitat due to afforestation by taking advantage of the increase in dove and pigeon populations [3]. They may also feed on poultry found in nearby villages [10], which have been inadvertently made available to them by humans. Larger individuals may also take on prey as big as a guineafowl [5]. The sparrowhawks often stalk their unsuspecting prey from above while remaining hidden in the trees before swooping down to capture the prey item [5]. Can carry prey up to 12 km, usually well above the canopy [5].
A. m. temminckii usually breed between August and November while A. m. melanoleucus breed between May and October [2]. 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 [6]. 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 [6].
The nests are made up of thousands of sticks collected by both parents and are usually lined with green eucalypt leaves, possibly to prevent pieces of meat from falling between the gaps and to deter carriers of diseases, such as mites and insects, due to the repelling smell of the leaves [11]
Black Sparrowhawks form monogamous pairs and are known to attempt multiple brooding; at any one time, a mated pair has more than one nest with offspring of different ages [12]. Typically a pair will lay 2-4 eggs and incubate them for about 37-38 days until they hatch [12]. The newly hatched chicks are semi-altricial 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 [12]. After 40 to 47 days, the juveniles are fledged but the parents will continue to care for them for the next 37 to 47 days [5]. The female usually lays a new clutch of eggs in her second nest about 60 to 90 days after her first clutch has fledged; both parents will then care for both nests [12]. Nests are often reused after the juveniles have left [12].