If you talk about a starling, most people in Europe and North America will picture a small bird with glossy black plumage. But that’s the common starling. It’s just one of 113 starling species, many of which have far more spectacular feathers. Just take a look at the selection above.
These resplendent plumes don’t just catch the eye. They may also explain why these birds are so diverse. According to a new study from Rafael Maia at the University of Akron, the starlings’ colours have made them more evolvable, accelerating their split into more and more species.
Many birds produce beautiful feathers using pigments that selectively absorb and reflect different colours of light. But starlings owe their most stunning colours to the structures of the feathers themselves.
As light hits the feathers, it encounters several layers. At each one, some light gets reflected and the rest passes through. If the layers are evenly spaced, the reflected beams amplify each other to produce exceptionally strong colours, which can easily change depending on the distance between the layers or the angle they’re viewed from. This effect is called iridescence. You can see it on the vivid throats of hummingbirds, the tail feathers of peacocks and the plumage of many starlings…