The influence of nest-site choice and predator sensory cues on nesting success in the Crimson Finch (Neochmia phaeton)

The attributes of a nest-site that a bird selects may be influenced by the potential predator species present, as different types of predator use different foraging strategies and sensory cues to locate nests. However, in many studies of avian nesting, the identity of the main nest predators and their foraging strategies are not known, limiting our interpretation and understanding of how choice of nest-site and nesting success might be linked. We investigated nest-site choice, nest survival and the nest predators in a population of Crimson Finch (Neochmia phaeton) in tropical Australia. Crimson Finches preferred to nest among foliage of the crowns of Pandanus on stems with aquatic barriers, and near old nests of conspecifics. However, none of these or any other attributes of nest-sites that we recorded significantly affected nest survival. Moreover, neither visual nor olfactory cues influenced nesting success in field experiments with quail eggs. Similar rates of predation of natural and experimental nests, coupled with similar rates of daily predation of eggs and nestlings suggest that predators were not using nest-attendance behaviour of the adult Finches as a cue to find active nests. Identified nest predators were reptiles; our study suggests that Crimson Finches may not be able to choose nest-sites that reduce the ability of these olfactory-driven predators.