These are three Gouldian finches, showing off the head color polymorphism present in this endangered species. Both males and females exhibit black, red, and yellow headed morphs - and there are incredibly interesting behavioral interactions based on color morph. Among the females, the redheads are the most aggressive, dominating both black and yellow morph females. Though, when red morphs are experimentally pigmented to look like black morphs, they lose to other red females. These birds are also choosy about mates, preferring to mate with other individuals of the same morph. In an interesting intersection of behavior and sensory input, they specifically need to use their right eye to reliably make this mate choice. Since mating with individuals of the same color morph produces more viable and robust offspring, it appears that there may exist the kind of selective pressure that could lead to a speciation event - where each color morph becomes a distinct species. Much of the fascinating work on this species comes from Sarah Pryke and her research group.