Breeding biology, demography and success of the rufous-banded honeyeater, Conopophila albogularis, in Darwin, a monsoonal tropical city

Abstract

The rufous-banded honeyeater, Conopophila albogularis, is probably the commonest small bird species in the suburbs of Darwin, Northern Territory. Nearly twenty pairs of this species were colour-banded on the Casuarina campus of the Northern Territory University, where they occupied territories of 0.15–0.47 ha all year-round, indicating a density of up to 12 birds ha^-1. Six out of 48 birds survived 5 or more years, one individual being 9 years old at the time of writing. Males were larger in the four morphological dimensions measured. Breeding behaviour was recorded in every month of the year, but was concentrated in the late dry and wet seasons (September–March), commencing about two months before the rains. Over half of 274 nests were built in black wattles, Acacia auriculiformis, a common pioneer species both within urban Darwin and monsoon rainforest ecotones of the Northern Territory. Contrary to the literature, both sexes participated in building the nest, and the incubation and nestling periods each lasted 14 days. The clutch size was usually two (78%), and mean clutch size for 85 nests was 2.1 eggs. Nest success was about 70%, hatching success of eggs was 74% and fledging rate of nestlings 87%. Four broods per season were common, and two pairs successfully raised five broods in one season. Average annual pair productivity was 5.8 fledglings (possibly the highest yet recorded for an Australian passerine species), one pair raising a remarkable 32 young over five seasons (6.4 fledglings per season). The exceptionally high nest success and productivity were probably mainly due to the scarcity of predators, and the long breeding season, respectively, the latter being facilitated by artificial watering of gardens and lawns during the dry season. The colonising success of this species in Darwin is attributed to Darwin’s coastal location and the close proximity of favoured natural habitats, as well as the generalised diet of the species and its predilection for the abundant black wattle.