[order] ACCIPITRIFORMES | [family] Accipitridae | [latin] Butastur rufipennis | [UK] Grasshopper Buzzard | [FR] Busautour des sauterelles | [DE] Heuschreckenteesa | [ES] Busardo langostero | [NL] Sprinkhaanbuizerd | [Authority] Sundevall, 1851

Grasshopper Buzzard determination

Members of the genus Butastur are medium-sized hawks, with long and pointed wings, and a medium length tail. The bill is rather weak, the basal portion and cere being brightly coloured. The legs are relatively short and reticulate, with a row of larger scales down the front. The colour pattern is subdued, rufous brown, grey and whitish. The young are not very different from adults. Butastur is found in Africa and tropical Asia. The four species form a super-species; though there may be some overlap between two of them. One nests in Japan and north Asia, but is highly migratory.

copyright: Mark Sutton

The adult Grasshopper Buzzard Eagle is grey brown above, darker on the head, with dark shaft streaks to all feathers. The feathers of the mantle and lesser coverts are narrowly with fringed rufous in fresh plumage, although this disappears as the feathers wear. The tail is grey, with faint brown bars. The greater coverts and primaries are light rufous, the latter being tipped with black, forming a conspicuous reddish patch when in flight. Secondaries flight feathers are rufous, dark brown towards the tip, which is white. The chin and throat are white or buff, with three black streaks on either side of throat. Below it is rufous, the breast having narrow shaft streaks of black, the belly and thighs being unmarked. Axillaries are grey-brown, spotted with white or buff. The under wing coverts and wing lining are white. The eyes, legs and cere are yellow. The beak is yellow at its base, with a black tip. The talons are black. The female is only slightly larger than the male. Young birds have a bright rufous head and nape with dark shaft streaks. The feathers of coverts and mantle are grey/brown with rufous tips, and the primaries and secondaries have white tips in fresh plumage. With age the crown assumes the same colour as the back, the tail acquires bars, and the edging of rufous on the mantle and coverts becomes less distinct.

It is found only in open savannah country and semi-desert tbornbush, never in forests. Within its range this species is migratory, breeding in the northern part between between March and May, remaining in the north for the rainy season, and migrating south during September. In West Africa the birds move south in September to October. In East Africa the movements are less clear, but it is found in Eritrea from June to October, passes through Somalia, probably moving south, in October, and occurs in Kenya and Tanzania between October and February, frequenting arid thornbush areas, and avoiding the worst of the equatorial short rains season, between October and December. In West Africa it is far more numerous than in East Africa, often seen in numbers together, while in East Africa it is normally found in groups of only abut ten. In its winter or dry season, non-breeding quarters, it is found in areas of savannah, grassland, or cultivation. On its way to winter quarters it appears in large numbers, attracted by grass fires, when fifty or more may be seen together. Later it takes up a temporary territory, and the same bird may be seen in the same patch of bush, perching on the same trees day after day. When not perching it flies low, quartering the ground with a buoyant flight, rather like a harrier, but with longer glides and erratic upward swoops. On the move it may fly high, up to 3,000 feet above ground level

This bird subsists almost entirely on insects, especially grass hoppers driven in front of a grass fire or termites after rain. It may also take small ground mammals and reptiles. Insects are caught in flight or on the ground.

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). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size has not been quantified, but it is not believed to 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.

The Grasshopper Buzzard Eagle breeds in the northern part of its range, laying in the Sudan in March, Somalia in April, and Northern Nigeria in March. It builds a nest rather like that of a kite, a structure of sticks about thirteen inches across by fifteen deep, with a cup in the centre about six inches across, lined with green leaves. The nest may be in a low tree, or up to 35 feet up in a big tree, according to locality. One to three eggs are laid. They are bluish white, almost glossless with a few speckles, spots and streaks of brown and chocolate or rufous, with some obscure lilac undermarkings. The incubating bird sits very tightly.

A widespread and common intra-African sub-Saharan migrant, moving across22 degrees of latitude, South to the border of Guinea woodland and forest during the October-March dry season, when fires and grazing reduce cover, then departing N with first heavy rains to breed in semi-arid steppe during March-September. Also non-breeding migrant to East Africa, moving North through Taru Desert of lowland Kenya in January-March, and through North West Somalia in September-October. Well studied only on non-breeding range of West Africa.

Range: Africa : East, Central, West. The Grasshopper Buzzard Eagle can be found in tropical sub-Saharan Africa from Senegal to Somalia and Eritrea and migrating as far as southern Tanzania in the non-breeding season.