Greater Flamingo (Phoenicopterus ruber)

The flamingo is a tall, rangy bird, with long spindly legs and an equally long neck. The legs, bare right up to the body, enable it to wade in deep water, and the long neck ensures that, while wading, it can reach right down to the ooze on the lake bed, at its feet. The front toes are webbed to give extra support when standing or walking in soft mud, but a flamingo is also quite capable of swimming when necessary. A flamingo feeds by filtering the water and mud for a limited range of invertebrates. While the bird is feeding the head is immersed in the water, upside down and facing backwards.

The strange, bent bill never quite shuts, but leaves a permanent crack between the mandibles of between 4-6mm. When the bird is feeding, the tongue moves back and forth into the mouth cavity several times a second, and in doing so it draws water in and out through this gap to form the basis of a filtration system. Large particles of 6mm diameter or more are excluded from entering, but smaller ones are drawn in. The inner edges of the mandibles are fitted with a network of tiny projections and hairs, and when water flows out these form a physical barrier to small particles in suspension, which are trapped. In this way the Greater Flamingo can filter out items as small as 0.5mm in diameter. The characteristic kink in a flamingo’s bill is necessary to maintain an even gap between the mandibles; if the bill were straight the gap would gradually increase along its length, and be too narrow for filtration at the base, and too broad at the tip.

Greater Flamingos are drawn to highly saline or alkaline water; this is their niche, and few other water birds can cope with it, so they have little competition. The range of food is limited, and in Europe flamingos mainly feed on brine shrimps (Artemia), which concentrate in vast numbers. A by-product of their unusual habitat is that Greater Flamingos also ingest algae when feeding, and these make the carotenoid pigments that give flamingos their unusual colour.

When feeding is good, the colour stimulates the birds to breed. The first signs are spectacular group displays, in which the birds may, for example, lift their necks up in synchrony, and then turn them from side to side rhythmically, a manoeuvre known as “head-flagging”. Before long, the mood shifts towards nest-building, and the birds create sandcastle-like structures of mud, with a shallow top, on which the single egg is laid. Uniquely, once they hatch the young are fed on a fat and protein-rich “milk” made by the adults and secreted from the crop. This unusual food is probably necessary for giving the young a good start in their difficult and challenging environment.

Habitat Open, extensive lakes or lagoons with shallow (‹1m depth) saline water.
Food A wide range of small or minute invertebrates filtered from the mud, including insects, crustaceans, molluscs, worms; also algae and diatoms.
Movements Erratic, but present all year in some places. Doesn’t necessarily breed every year – it depends on the water level and productivity of potential sites. May commute long distances to feed.
Voice A range of honking and cackling sounds.
Pairing style Monogamous, but pair bond probably for one breeding attempt only.
Nesting Highly colonial, in dense and often enormous colonies divided into sub-colonies.
Nest A cone of mud 30-40cm high with a surprisingly slight cup on the top.
Productivity 1 brood a year.
Eggs 1.
Incubation 28-31 days, by both parents in long shifts.
Parenting style Both parents feed young at the nest, and then at the crèche.
Food to young A unique type of milk, regurgitated from the adults’ crop.
Leaving nest Young remains in the nest for 5-12 days; it is then able to walk and join a crèche. The parents continue to feed it, recognising it in the mêlée by voice, for up to 70 more days.