Why are flamingos pink?

Flamingos filter-feed on algae, tiny crustaceans and brine shrimp that are rich in carotenoids, the same family of pigments that makes carrots orange. The birds’ livers break these pigments down into pink and red compounds, which are then deposited in their growing feathers, skin and even egg yolks. Chicks hatch with grey or white down and take around two to three years to reach their adult colour. A flamingo that stops getting enough carotenoids will slowly fade as it moults. Zoos therefore add pigments such as canthaxanthin to the birds’ food to keep them bright.