Page:Ibis - Series 11 - Volume 3.djvu/139

1921.] exactly the same changes of plumage are apparent in the ten birds from Nyasaland.

In dealing with examples of the Black Cuckoo from north-east and north-west Africa the problem is considerably complicated by the occurrence in Uganda, British East Africa, southern Abyssinia, and northern Angola of the bird known as Cuculus jacksoni Sharpe, immature examples of Cuculus clamosus having been confused by many workers with the young of C. jacksoni. Unfortunately both forms occur side by side in many districts—even in the same forests; and the very variable plumage exhibited by immature birds of C. clamosus has made the status of the two forms and the range which they occupy a difficult task to unravel.

From northern central Africa we have examples of the true Black Cuckoo from Uganda, British East Africa, southern Abyssinia, eastern Belgian Congo, the Galla country, Niam-Niam country, northern Angola, Gold Coast, and Sierra Leone. The adult black birds are indistinguishable from those from South Africa, and the immature specimens exhibit the same remarkable variety in the colour of the plumage—from the indistinctly barred birds with an indication of rufous appearing amongst the feathers of the breast to a curious grey bird in the collection of Sir Frederick Jackson.

[Cuculus jacksoni Sharpe, Bull. B.O.C. xiii. 1902, p. 7—Type locality: Toro, Uganda.]

At first glance typical examples of C. jacksoni look like a very distinct Cuckoo, but the type is not quite adult. The upper parts are glossy blue-black as in C. clamosus, but the underparts are very dissimilar to any phase of plumage exhibited by South African specimens in the National Collection, and resemble much more nearly C. g. gabonensis. The breast is dark chestnut, the throat greyish, and the rest of the underside, from the chest to and including the under tail-coverts, is strikingly banded with black