Chick survival in the megapode Alectura lathami (Australian brush-turkey)

Abstract

Megapode chicks live independently from the time of hatching and are thus ideal subjects for investigations into how the lack of parental care can affect chick survival. Here, we present such results for chicks of the Australian brush-turkey (Alectura lathami), radio-tracked in two smallremnant rainforest patches (Mary Cairncross Rainforest Park and Aplin Forest) from their second day of life. Mortality was 88–100% during the first three weeks after hatching. It did not differ between two breeding seasons at Mary Cairncross Rainforest Park, as evident from comparisons of average survival time (in days) and Kaplan–Meier survival estimates. Survival differed, though, between the two sites in the same breeding season: the average survival time was significantly higher at Aplin Forest (8 days compared with 3 days) and the Kaplan–Meier survival estimates decreased less sharply. Predation by cats and birds of prey exerted the greatest influence on survival, but the proportion of deaths caused by these two predators was approximately the same at both sites. The main factor affecting survival was obviously the availability of thickets, which were more abundant at Aplin Forest. The survival rates of chicks released in thickets was significantly higher than of those released in the rainforest, presumably because they were better protected from predators. For chicks living in thickets the likelihood of being killed was lower than expected, but it was higher for those remaining in rainforest. On the basis of these results, we propose that management plans for endangered megapodes should include the identification and protection of large protective thicket habitats for enhancing overall chick survival, apart from controlling introduced predators such as feral cats.