The Comparative Breeding Ecology of Two Species of Euplectes (Bishop Birds) in Usambara

Abstract

EUPLECTES NIGROVENTRIS CASSIN, the Zanzibar red bishop, and Eh hordeacea (Linn.), the crimson-crowned bishop, are weavers of the subfamily Ploceinae. On the biology of the former species nothing appears to have been recorded hitherto except the notes reproduced by Reichenow (1904) and those of Vaughan (1929), who (rightly) suspected it to be polygamous. For Euplectes hordeacea we take the work of Lack (1935) as basis and amplify only certain points. Our study is more incomplete than we should have wished because we could not make continuous observations and because of an unexpected technical difficulty. The males of both these bishop birds have a highly conspicuous red breeding dress and are at other times practically indistinguishable in the field from females and young. Both are territory-holding species dependent on grasses for their food and their nesting materials. The architecture of their nests, which are similar except in size, demands close upright vegetation. The rather restricted geographical range of E. nigroventris is wholly contained in that of E. hordeacea. The two species may often be found side by side, but in our experience there is little ecological overlap; the smaller E. nigroventris