Aspects of the breeding biology of the Chinspot Batis Batis molitor in Acacia savanna in Swaziland

Some aspects of the breeding ecology of the Chinspot Batis (Batis molitor) were studied in Mlawula Nature Reserve, north-eastern Swaziland. Nests were predominantly built in thorny bushes or trees. Eggs were laid between 20 September and 2 January. However there was a definite peak in November, during which the majority of eggs were laid. Nesting success in the Chinspot Batis was over 30%, while fecundity was 0.65 fledglings/pair/annum. Except for a single occasion, pairs did not double brood unless breeding failed or fledged chicks disappeared. Replacement nests, however, were the norm where a previous nest had failed. Adult batises were observed to feed predominantly on caterpillars and moths. Observations at the nest confirmed that batises fed predominantly moths and caterpillars to their nestlings. The rate at which nestlings were fed depended on their age, older chicks being fed more frequently than younger ones. The correlation between feeding rate and nestling age, and between feeding rate and fledgling age, was significant. In contrast to nestlings, younger fledglings were fed at a higher rate than older ones.