No – flamingos are pink on the inside, too. These flamboyant birds are adapted to collect and metabolise carotenoid pigments – the chemicals found in algae, crustaceans and microscopic plant materials that form tones of orange, red, yellow and pink.
Though the pink coloration is most obvious in a flamingo’s plumage, the carotenoids also impregnate the bird’s tissues, skin, blood and even egg yolk.
Flamingos are among a select few birds that feed their young directly from a secretion produced in their crop (throat), and even this ‘crop milk’ is bright pink.
Interestingly, so much carotenoid is taken up by their eggs and crop milk that by the end of a breeding season parents of both sexes have lost the pink colouring from their feathers and appear almost white.
Scientists have found that the blood biochemistry of each of the six flamingo species varies, with different species seeking specific types of carotenoid. This accounts for the range of hues.
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