Why are red birds red?

How do some birds get their exotic scarlet plumage?

Resplendent in red: the scarlet tanager © Trevor Jones Photo/iStock

Scientists have identified the gene responsible for making the red pigments in many birds’ feathers and skin – a discovery that provides a big clue for why the colour is so important in avian sexual displays.

Advertisement

Red pigments must be manufactured physiologically by birds, because unlike yellow ones, for example, they cannot be obtained directly from their diet.

But two separate studies – one on zebra finches, the other on a red breed of canary – have identified a single gene that codes for an enzyme that converts yellow pigments to red ones.

Intriguingly, the enzyme is also produced in large quantities in the liver, where it breaks down toxins. Producing all of that enzyme probably takes a lot of energy, and only the fittest, strongest birds are likely to be able to produce enough of it.

Miguel Carneiro of the University of Porto, Portugal, who led the canary study, said: “This might explain why variation in the intensity of red coloration appears to be an indicator of individual quality, and why red coloration of bills and feathers evolved independently so many times.”

Source Current Biology


Advertisement

Main image: Resplendent in red: the scarlet tanager © Trevor Jones Photo/iStock