A simple method to collect viable rainforest tree seeds and study the frugivorous diet of satin bowerbirds (Ptilonorhynchus violaceus)

Abstract

For more than 100 years, behavioural biologists have extensively studied satin bowerbirds (<i>Ptilonorhynchus violaceus</i>) to understand the complexities of bower construction and courtship, but this research has not accounted for the ecologically important role the species plays as a seed disperser in eastern Australia. In this study, we have used a simple method involving pans of water and mirrors to collect scats from male satin bowerbirds on the Dorrigo Plateau of northeastern New South Wales. Based on seeds identified from scats collected using this method, we identify the fruits of 37 plant species in 22 families that are eaten by satin bowerbirds and show that 35 of these species germinated after passage through the digestive system of bowerbirds. This method was developed for bush regenerators to collect rainforest tree seeds that are otherwise inaccessible and/or difficult to germinate; it is applicable throughout the range of satin bowerbirds. We hope the method will be adopted by bush regenerators for harvesting seeds otherwise difficult to source, and by ornithologists studying the diets and seed dispersal of these ecologically significant birds.