What Do Flamingos Eat? Upside-Down Filter Feeding Explained

How flamingos feed

A feeding flamingo wades into shallow water, lowers its long neck and turns its head upside down between its legs. In this position the bend in the bill lets it lie flat against the water or the bottom. Unlike almost all other birds, the flamingo moves its upper jaw rather than its lower one.

The bill works like a pump and a sieve together:

• The tongue is thick and fleshy. It moves back and forth several times a second, sucking water and mud into the bill and pushing it out again.
• The lamellae are rows of fine, comb-like plates along the edges of the bill. They trap food particles while water and silt are squeezed out.
• The feet help too. Flamingos stamp and shuffle, or walk in tight circles, to stir up food from the bottom.

A 2023 study of Chilean flamingos found that these movements also create small whirlpools in the water that concentrate prey near the bill, a little like a living vortex trap. Flamingos can feed for hours, by day and at night. In deeper water they may swim and up-end like ducks to reach the bottom, and the lesser flamingo often feeds while swimming, sweeping its bill through the surface layer.

What do flamingos eat in the wild?

Their food includes:

• Small crustaceans: brine shrimp, copepods and other tiny shrimp-like animals.
• Insect larvae: especially midge larvae (chironomids) and brine fly larvae, which live in huge numbers in salty mud.
• Mollusks and worms: small snails, tiny clams and worms dug from the bottom.
• Plant food: seeds of water plants, and in some places rice and other grains.
• Microscopic algae: diatoms and blue-green algae (cyanobacteria), which are the main food of some species.

Many of these foods are rich in carotenoid pigments, which is why flamingos turn pink. The full story is in why are flamingos pink?

How diets differ between flamingo species

There are six flamingo species, and their bills fall into two broad types. Species with a shallow-keeled bill have coarser filters and take larger food, mostly from the bottom. Species with a deep-keeled bill have very fine filters for microscopic food.

Because they eat different foods, species can share the same lake without competing much. In East Africa, greater and lesser flamingos often feed side by side: the greater flamingo works the bottom for invertebrates while the lesser flamingo skims algae from the surface. The lesser flamingo has the finest filter of all and can strain out cyanobacteria such as Arthrospira (spirulina), which turns the alkaline Rift Valley lakes green.

Why flamingos live on salty lakes

Flamingos often feed in water that is too salty or alkaline for fish. That is an advantage, not a hardship. Without fish to compete with, brine shrimp, fly larvae and algae can build up in enormous numbers, providing a rich food supply for anyone able to filter them.

To cope with the salt, flamingos have salt glands above the eyes that remove excess salt from the blood; the salty fluid drips out through the nostrils. They still need fresh water to drink and will fly to springs, streams and rain pools, or drink rainwater.

What do flamingo chicks eat?

Newly hatched chicks have a straight bill and cannot filter food. Both parents feed them crop milk, a nutritious fluid rich in fat and protein produced by glands in the upper digestive tract and dribbled into the chick’s mouth. Flamingo crop milk contains red pigment, and hard-working parents often turn paler during a long breeding season.

As the chick grows, its bill bends and develops lamellae, and it gradually learns to filter feed for itself at around two to three months old.

Myths about what flamingos eat

Flamingos only eat shrimp. Brine shrimp are important for some flamingos, but larvae, mollusks, seeds and algae are just as important, and some species eat almost no shrimp at all.

Flamingos eat fish. Fish are at most an occasional accidental item. Flamingos have no teeth and their bills are built for tiny food.

Flamingos stir mud with their bills. The bill is mainly a filter. Stirring is done mostly with the feet, while the bill pumps and strains the water. For another famous flamingo behavior, see why do flamingos dance?