THE BREEDING BIOLOGY OF THE BLACK‐FACED DIOCH QUELEA QUELEA IN NIGERIA

SUMMARY A study of the breeding biology of Quelea quelea in Nigeria, and particularly at a large breeding colony near Lake Chad, showed that losses of eggs and young were extremely small. 95% of eggs laid hatched successfully, and 87% give rise to fledglings. Nestling deaths were density‐dependent and apparently due to starvation. The incubation period was 10 days or less. By day, eggs were heated to 34°‐ 37° C. by the sun; at night the females incubated. The nestlings were initially fed mainly on insects, their diet gradually changing to one of seeds—mostly of the grass Echinochloa pyramidalis . The deep body temperatures of young birds were determined. It is suggested that the nestlings left the nest after, on average, 11 1 / 2 days to escape intolerable temperature conditions in the nest. Fat reserves were accumulated by nestlings and fledglings, and were utilized when the young became independent. The adults put on fat during the incubation period and lost it during the time spent feeding nestlings. It is concluded that the most common clutch‐size of Q. quelea , which is everywhere three, corresponds to the largest number of young the parents can normally nourish. This conforms to Lack's theory on the significance of clutch‐size, and gives no support to Skutch's opinion that the theory does not apply to tropical birds.