The Superb fairy-wren is often described as one of the most “polyamorous” birds in the world. Although males and females form long term social pairs and defend a territory together, they are rarely sexually exclusive. Most chicks in a nest are actually fathered by males outside the social pair.

During the female’s fertile period, she may quietly visit neighboring territories before dawn to mate with other males. At the same time, males advertise themselves with early morning song displays and bright blue breeding plumage. Genetic studies have shown that a large majority of offspring, often more than two thirds, are raised by extra pair males.

What makes this system even more striking is that males and helpers still feed and defend chicks even when they are not genetically related to them. The result is a socially monogamous bird with a highly polyamorous genetic mating system, driven largely by active female choice.

Stickers are about 10cm big