Flamingos in the wild use pigments as "cosmetics" to enhance the colour of their plumage, according to scientists.
"Researchers studying greater flamingos in the wetlands of southern Spain found that the birds rubbed pigmented secretions onto their feathers.
They produce the pigments in glands near the base of their tails.
The scientists describe in the journal Behavioural Ecology and Sociobiology how the birds use the pigments to signal to potential mates.
The researchers identified pigments called carotenoids in the mixture of wax oil that the birds secrete in their preen glands.
They noticed that, as well as smoothing and tidying their feathers, many birds deliberately rubbed their cheeks against the preen gland and then immediately onto their neck, breast and back feathers.
Reddish-orange carotenoid pigments in the oils then brightened the signature pink hue of the birds' feathers....."
