The Bird Fauna of a Deciduous Woodland in the Wet-Dry Tropics of Northern Australia.

Abstract

Censuses of birds were made monthly from October 1986 to October 1987 in a deciduous woodland in the Australian Northern Territory. Additional limited counts of granivorous birds were made in March and April 1988. The woodland was selected for the study because it contains a population of the endangered Gouldian finch (Erythrua gouldiae). The species composition of birds was temporally unstable; this was associated with the marked wet-dry seasonality. For some foraging groups (e.g. nectarivores, foliage-gleaners), diversity was correlated with resource availability. Although the species composition of birds of this site is not very similar to that of any other surveyed area, it falls within the range encompassed by that of woodlands across tropical Australia, and is distinct from that of open and closed forests in the same region. Tropical savanna woodlands and open forests differ in composition of their foraging groups compared with their temperate counterparts. The species richness of granivores, hawking insectivores, nectarivores and terrestrial omnivores at this site is unusually high. The changing composition of bird species in this tropical woodland site suggests that many birds in this environment undergo substantial regional movements. The conservation of such species demands large and heterogeneous reserves, a strategically located reserve system and/or sympathetic management of land outside reserves.