Birds
Flamingo
Phoenicopterus roseus · also called greater flamingo
The flamingo is one of the most recognisable birds in the world and one of the strangest in its habits: it filters its food from mud with an upside-down head, wears a colour it manufactures from its diet, and nests by the tens of thousands on lakes too hostile for almost anything else.
Overview
The greater flamingo is the largest and most widespread of the six flamingo species, found on saline and alkaline wetlands from West Africa and the Mediterranean to India. Flamingos are nomadic, tracking water and food across huge distances — a lake that is crowded with birds one year can be empty the next as conditions change. They fly at night in long lines and V-formations, necks and legs outstretched.
Built to filter
Everything about a flamingo’s feeding equipment is specialised:
- A downward-bent bill that works the right way up only when the head is inverted.
- Lamellae — comb-like rows inside the bill — that strain tiny food items from water and silt.
- A large, muscular tongue that acts as a pump, driving water through the sieve several times a second.
- Long legs and a long neck to reach the water surface while wading, and webbed feet to stir prey from the mud and to swim in deeper water.
The diet — brine shrimp, blue-green algae, diatoms, small molluscs and insects — is also the source of the bird’s pink to red colour, built from carotenoid pigments the flamingo extracts and redeposits in its feathers and skin.
Colonies
Flamingos are intensely social and breed in dense colonies, sometimes more than 20,000 pairs, on open mudflats and islands in shallow lakes. The colony performs synchronised group displays — head-flagging, wing salutes, marching in tight packs — that bring the whole flock into breeding condition at once. Nesting on caustic soda lakes and hypersaline lagoons is a defence: the water chemistry excludes most predators and competitors.
Reproduction
A pair builds a truncated cone of mud 15 to 45 cm high and the female lays a single chalky white egg. Both parents incubate it for around a month, then feed the hatchling on crop milk — a rich red-pink secretion from the parents’ upper digestive tract, produced by both sexes. After a week or two the grey, straight-billed chicks gather into large crèches of thousands, guarded by a few adults, while parents forage; each adult still finds and feeds its own chick by voice.
Threats and conservation
The greater flamingo is listed as Least Concern and is increasing in parts of its range, having recolonised southern France and Spain and expanded around the Mediterranean. Local threats remain serious, however: the small number of suitable breeding lakes makes colonies vulnerable to water extraction, changing lake levels, mining (notably proposed soda extraction at Lake Natron), disturbance, lead poisoning from spent shot, and collisions with power lines.
Flamingo: common questions
Why are flamingos pink?
Entirely because of what they eat. Flamingos feed on algae and on small animals like brine shrimp that are rich in carotenoid pigments — the same family of compounds that makes carrots orange and salmon flesh pink. The bird's liver breaks the carotenoids down and deposits them in growing feathers, skin, and bill. A flamingo denied these foods gradually moults to pale grey or white, which is why zoos add carotenoid supplements to their feed. Brighter birds are healthier and better fed, and they use colour in mate choice.
How does a flamingo actually eat?
It feeds with its head upside down and its bill pointing backwards, submerged in shallow water or soft mud. The tongue pumps water and sediment in and out of the bill several times a second, and rows of hair-like plates called lamellae along the bill edges act as a sieve, trapping brine shrimp, algae, diatoms, and tiny seeds while letting the water and silt flow back out. It is the same filter-feeding principle a baleen whale uses.
Why do flamingos stand on one leg?
The leading explanation is that it costs almost no muscular effort — a flamingo can lock the standing leg into a stable position and essentially balance passively, even while asleep. Standing on one leg also reduces the amount of body heat lost to cold water, since a bare leg is a major route for heat loss. Flamingos switch legs periodically and stand on two when walking or feeding actively.
Where do flamingos raise their chicks?
On some of the harshest water on Earth. Many colonies breed on shallow, highly alkaline or salty lakes — Lake Natron in Tanzania is caustic enough to burn the skin of other animals — precisely because the hostile chemistry keeps predators away. Pairs build a cone of mud with a shallow cup on top, lay a single egg, and both parents feed the grey chick on a bright red "crop milk" secreted from the upper digestive tract.