American Flamingo (Phoenicopterus ruber) Fact Sheet: Diet & Feeding

• Filter feeders
• Diet
• Small crustaceans (such as amphipods)
• Molluscs
• Insects (such as midges and brine flies)
• Polychaete worms
• Fish (rarely)
• Widgeongrass seeds, muskgrass tubercles, and algae
• One flamingo needs ~32,000 brine-fly chrysalids or 50,000 larvae per day.
• Sometimes swallow mud to obtain nutrients and microorganisms, such as bacteria, and protozoa.
• Swallowing rough granuals of sand or stone makes the gizzard more effective in grinding up shelled organisms like snails.
• Young are fed "crop milk", which is produced by glands lining the upper digestive tract, rather than in the crop. The milk contains a high level of fat and nutrition.

Feeding mechanism

• Head held upside down in shallow water (beak parallel to waterline), sweeping side to side.
• Tongue pumps water in and out of beak like a piston (5-6 times/second). Backward curving spines on tongue help guide food to the throat. For larger food particles, the beak is used as the pumping mechanism.
• Food particles are strained out of the water through the lamellae.
• Top bill not fixed to the skull, but moves up and down during the filtering process. Mammals and other birds have a fixed upper jaw.
• Also feed by picking up larger prey in their beak and swallowing (uncommon).

Six feeding behaviors (described by Rooth (1965))

• Skimming: moving beak back and forth in the top layer of water; mostly used for plankton
• Grubbing: up-ending, like a dabbling duck; used to feed along the bottom of meter-deep water. Long legs and neck permits feeding in areas that are deeper than those used by other waders.

• Walking and seizing with beak, as with use of forceps
• Stamping -"marking time": standing in one place, lifting feet up and down; in muddy bottoms; flushes out prey
• Stamping in a circle: around the bill, which is at the center; a small mound is formed, surrounded by shallow moat; in shallow water.
• Running: along the bank, stabbing at prey with forceps-like motion; similar to feeding activity of  small herons.
• Walking, the beak tip leaving a trail: very shallow water; used for scooping mud and filtering out microorganisms.

Water

• Often do not have access to fresh water
• Will drink rainwater when available
• Have a salt excreting organ above the eye similar to that seen in other sea dwelling vertebrates (gulls, turtles, etc.).

A 2-day-old American Flamingo chick curls up next to its mother for warmth at the San Diego Zoo.

After hatching, the chicks stay close to a parent, sitting with the mother or father for the first 5 to 7 days on a nest mound created for the chick.

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.

Arengo & Baldassarre (2002)
del Hoyo et al. (1992)
Ehrlich, et al. (1988)
Rooth (1965)
Zweers et al. (1995)