Juvenile dispersal and habitat selectivity in the megapode Alectura lathami (Australian brush-turkey)

Abstract

Dispersal and habitat selectivity of young precocial birds is usually determined by parents, as these lead their chicks after hatching. Megapode chicks receive no parental care and little is known about factors determining their dispersal and habitat selectivity. Here, we present such results for the Australian brush-turkey (Alectura lathami). Chicks were radio-tracked in two small remnant rainforest patches (Mary Cairncross Rainforest Park and Aplin Forest) from their second day of life and for up to 30 days. At Mary Cairncross Rainforest Park, the median dispersal distance was significantly affected by age, as it decreased from approximately 100 m on each of the first five days to around 50 m per day thereafter. At Aplin Forest, age had no significant effect on dispersal. The difference between the two sites can be explained by incorporating habitat selectivity. Chicks preferred to stay in thickets and avoided the more open rainforest, as evident from time selectivity indices calculated for both habitats. At Aplin Forest, 31% of the area was covered by thickets, such as lantana (Lantana camara) and raspberry (Rubus ssp.), whereas at Mary Cairncross Rainforest Park this proportion was only 6%. Management plans for endangered megapodes should consider the role of thickets in the chicks' dispersal behaviour, and thus in population spread, recolonisation and gene flow.