What pigment makes many flamingos pink after they eat algae and crustaceans?

Carotenoids make many flamingos pink after they eat algae and crustaceans containing these pigments. The birds absorb and process carotenoids in their diet, then deposit related pigments in feathers, skin, and egg yolks.

Flamingos feed in shallow lakes, lagoons, and coastal wetlands. Their specialised bills strain tiny organisms from water and mud, including algae, diatoms, and small crustaceans. The exact shade varies among species and depends on diet, age, health, and breeding condition. Well-fed birds may appear bright pink or reddish, while birds receiving fewer carotenoids can look much paler.

Flamingos are not naturally pink because of a pink feather structure. Their colour is dietary, which is why captive birds must receive suitable sources of carotenoids to maintain normal plumage. Carotenoids are a broad group of pigments also found in carrots, pumpkins, many algae, and other organisms. In flamingos, the compounds can be transformed into pigments such as canthaxanthin.