Project

Dispersal and sociality in cooperatively breeding purple-crowned fairy-wrens

Many animals live in social groups, yet we do not fully understand why, especially when this means they give up their own reproduction. Why do individuals forego reproduction and stay in a group? Why do they not move elsewhere and breed independently? These are the questions we need to answer to understand the evolution of social living.

In this project, we unravel dispersal decisions and their consequences by combining detailed individual behavioural observations, novel molecular approaches, and state-of-the-art tracking technologies to purple-crowned fairy-wrens. This allows us to reveal which individuals stay or (attempt to) disperse, how costly it is to disperse, and how dispersing vs staying affects ultimate reproductive success. This will reveal how costs of leaving and benefits of staying at home drive different dispersal strategies, to elucidate the selective forces that ultimately drive the evolution of sociality.

Purple-crowned fairy-wrens offer a great model system for studying sociality. These birds are cooperative breeders endemic to northern Australia. They inhabit and disperse exclusively along waterways rich in native Pandanus aquaticus palms. Young can either stay in their natal group until they inherit the breeding position, disperse to a breeding position nearby, or disperse long distances to a different habitat fragment, making them well suited for studying group living and dispersal. A population of these birds has been studied in the Kimberley region in northwest Australia since 2005. All birds are individually recognisable by a unique set of colour-rings, and followed throughout their life, so we can link behavioural data to individual fitness.