Breeding ecology and ornamentation in the long-tailed finch

The Long-tailed Finch (Poephila acuticauda) is an endemic Australian grassfinch (Estrildid) inhabiting the tropical northern savanna of Australia. Ecologically it is very similar to the well-studied Zebra Finch (Taeniopygia guttata) and the endangered Gouldian Finch (Erythrura gouldiae) - sharing the same geographic range, but yet has not declined. -- Here, in the first extensive field study of the breeding ecology and behaviour of this species, I describe the general breeding ecology of the Long-tailed Finch including mate and site fidelity while drawing a comparison with the zebra finch, and also describe the first observation of cooperative breeding ever recorded for this species. -- The Long-tailed Finch possesses several putative ornaments in both sexes including elongated tail streamers, a black throat patch and variation in bill colour. In this study I show that this species is slightly dimorphic in expression of ornamentation thereby removing evidence for the sexual indistinguishability theory. As pairs did not mate assortatively based on ornament expression, mate choice in this wild population did not seem to be based on ornament expression and ornament expression did not seem to signal reproductive success in males or females. This species has low levels of extra-pair paternity, but choice for extra-pair mates does not seem to be based on ornament expression or improve offspring quality. Parental nest visit synchrony is high in this species and has a limited effect on breeding success. Further, parental ornamentation does not signal parental quality and does not affect nestling growth. -- The mutual multiple 'ornaments' in this species therefore do not currently seem to be under sexual selection, but might play an important role in species recognition.