Fairy-wrens are cooperatively breeding small songbirds, that are renowned for their striking seasonal plumage in males, their complex reproductive strategy and above all their extreme unfaithfulness. We discovered that one of the genus, the purple-crowned fairy-wren, follows a faithful mating strategy, and this appears to have wide-ranging consequences for its mating behaviour, acoustic signals, plumage development, and the cooperative breeding system. Research on the purple-crowned fairy-wren is one of our main research foci, our field site is at the AWC Mornington Wildlife Sanctuary.

Incest, extra-pair paternity and territory quality drive divorce in a year-round territorial bird.
Hidalgo Aranzamendi N, ML Hall, SA Kingma, P Sunnucks & A Peters. 2016. Incest, extra-pair paternity and territory quality drive divorce in a year-round territorial bird. Behav Ecol 27 (6): 1808-1819

Purple-crowned fairy-wrens are quite constrained in their choice of a partner, and this paper showed how and when females can rectify this. An important driver is to escape an incestuous relationship, but females also divorce to obtain a better territory.

Breeding synchronization facilitates extra-pair mating for inbreeding avoidance.
Kingma SA, ML Hall & A Peters. 2013. Breeding synchronization facilitates extra-pair mating for inbreeding avoidance. Behav Ecol 24(6):1390-1397.

Female purple-crowned fairy-wrens can avoid high costs of inbreeding (reduced hatching success of eggs) by extra-pair mating. We show that females in incestuous pairings achieve high rates of extra-pair fertilizations by synchronising their breeding attempts with neighbours.

Male songbirds indicate body size with low-pitched songs.
Hall ML, SA Kingma & A Peters. 2013. Male songbirds indicate body size with low-pitched songs. PLoS ONE  8(2): e56717.

This study presents some of the first evidence in male oscine passerines for the widely predicted negative relationship between song frequency and body size, consistent with song functioning as an index signal of size.

Multiple benefits of cooperative breeding in purple-crowned fairy-wrens: a consequence of fidelity?
Kingma SA, ML Hall, E Arriero & A Peters. 2010. Multiple benefits of cooperative breeding in purple-crowned fairy-wrens: a consequence of fidelity? J Anim Ecol 79: 757-768.

We show that helpers at the nest provide important assistance: they increase food provided to nestlings, the number of young that leave the nest, and the survival of the parents of those young. Such extensive benefits are not found in other fairy-wrens. It seems that the price these birds pay for their high levels of extra-pair mating is reduced benefits of their ‘helpers’, as we demonstrated in a comparative analysis