Head Colour and Age Relate to Personality Traits in Gouldian Finches

Colour polymorphism is a widespread phenomenon in vertebrates and has often been linked with differences in behaviour such as aggression or boldness, behaviours that are often part of personality traits in monomorphic species. However, up to now, very few studies have looked whether colour morphs just differ in average behaviour or whether specific combinations of behaviours are favoured in relation to a particular morph therefore signalling personality traits. This was tested in the highly social and polymorphic Gouldian finch (Erythrura gouldiae). Tests were performed in pairs of a red-headed and a black-headed individual of same sex and size but different age. Capture rank in the aviary as well as latency to feed beside a novel object (neophobia) and to approach and touch a novel object on a perch (neophilia) were measured. For neophobia and neophilia, ranks of latencies calculated across all individuals were used and general and within-pair comparisons were made. Neophobia and approach neophilia were consistent over time (2 similar to mo), and approach neophilia was positively correlated with capture rank and neophobia indicating that the behaviours are part of personality traits. Moreover, black-headed birds generally approached the novel object earlier than red-headed birds. Similarly, within pairs, black-headed birds were first to approach the novel object and were also captured first. Relative age (younger or older than the partner) was related to neophobia and tactile neophilia ranks; older birds reacted faster. The results indicate that colour morphs not only differ in average behaviour but that specific combinations of behaviours are related to colour morphs suggesting that head colours signal personality traits. Furthermore, depending on age individuals may have different roles in a social network.