THE BEHAVIOUR OF THE WEST AFRICAN VILLAGE WEAVERBIRD

Summary A detailed description is given of the breeding behaviour of the West African Village Weaverbird Ploceus (Textor) cucullatus cucullatus, as observed in northwest Senegal, supplemented by observations of birds in large outdoor aviaries at Los Angeles, California. The essential pattern of breeding behaviour was the same in field and laboratory, with only minor differences. Both field and laboratory observations of behaviour were based on colour-banded birds and aided by analysis of motion-picture frames with a time-and-motion projector. In northwest Senegal the Village Weaverbird breeds during the short rainy season. But rainfall per se is not necessary to stimulate breeding, since our captive birds have bred well for ten years in the hot, completely dry Los Angeles summer. But neither a plentiful supply of food (grain, insects, lettuce) nor of nest material prevented birds kept in outdoor aviaries from ceasing to breed at the end of each summer. In this colonial and polygynous species the black-and-yellow males are strongly territorial and build the outer shell of the nest to which they attract the females by means of stereotyped nest-invitation displays. These displays are described in detail, with emphasis on the association between special colours and movements. In general, display of black predominates in aggressive displays given by a male toward other males and of yellow portions of the plumage in nest-invitation displays given by a male toward females. The chain of interactions between male and female gradually leading to acceptance of the nest by the female and to copulation is elaborated, together with the variations in this behaviour. As in the race graueri which we had previously studied in Central Africa, we found that the male tore down his own nest if it was repeatedly rejected by females, and would then build a fresh nest in its place. The female lines the bottom of the nest after she accepts it, does all of the incubating, and in this race does practically all of the feeding of the young, in contrast to the race graueri, in which the male often takes a considerable share. Self-maintenance, preening, resting, comfort and bathing activities are described. During rest periods, stretching movements of various sorts are common and conspicuous. In northwest Senegal, hawks (chiefly Accipiter shikra and Micronisus gabar) harassed the Village Weaverbird colonies daily, but no captures were observed. Snakes seem to be much more effective and serious predators. An instance of nocturnal predation on a Village Weaverbird colony by an African Python Python sebae was observed. The most favourable sites for nests in the colony tree were those in the safest situation from snakes, i.e. suspended from branches hanging directly over the water. It is suggested that such a site was an important factor contributing to the evolution of weaving in the true weaverbirds. Some comparisons are made with the behaviour of other species of weaverbirds. Local species differences in habitat distribution are partly attributed to differences in kind of nest materials required. Specific differences in the nest-invitation display are related to the male's need to facilitate access to the nest entrance by prospecting females.