American Flamingo (Phoenicopterus ruber) Fact Sheet: Physical Characteristics

General

• Tall, slender, wading birds with webbed feet.
• Neck and legs longer, relative to body size, than any other bird.
• Overall plumage color is a deep pink to red/orange; color may be darkest on rump, head, and neck.
• Black primary and secondary feathers.
• Beak with black tip, pink to red/orange middle, and pale yellow base near the eye; upper bill often lighter in color.
• Legs pink with slightly darker knees
• Thick bill with sharply down turned angle; Lower bill much thicker than upper.
• Odd shape is characteristic of the Family. Gap of an open beak is the same along entire length (=more efficient filtration); gap of straight bill would be much larger at tip.
• Inner surface of beak has rows of keratinous plates (lamellae), covered with tiny hairs (cilia) through which food is strained out of water. Similar in function to a baleen whale.
• Tongue fits into deep groove in lower bill and acts as a piston to pump water in and out.
• Proximal surface of tongue with 2 longitudinal rows of spiny protuberances that point towards the throat.

Plumage: Coloration and Molting

• See Life Stages for a description of the changes in plumage with age.
• Molting cycle is variable
  • Can occur gradually, so that there is no period of flightlessness.
  • Can occur simultaneously, as seen in waterfowl, resulting in a three-week flightless period. Most often observed in managed care populations.
  • Occurs from twice per year to every one or two years.
  • Common molting periods: (a) Just before breeding displays begin, contour feathers are replaced with full breeding plumage color, (b) Just after breeding, almost all feathers replaced, (c) Just before egg laying and during incubation, head and neck feathers may be replaced.

Pigmentation

• Bright pink of feathers, legs, and beak comes from carotenoids that are metabolized into several different byproducts (pigments) and deposited, through the blood, to different parts of the body.
• Pigments
  • Canthaxanthin (red), main pigment in feathers of all flamingo species; also found in roseate spoonbill, and scarlet ibis.
  • Astaxanthin (red), main contributor to skin color of legs, minor contribution to feather color.
• The carotenoids cannot be synthesized by the flamingo, but must be ingested.
• Because there is no blood supply to the feathers once they have finished growing, it is not known how the color is retained by the animal.

• Females up to 20% smaller than males
• No overlap in body size

Comparison with other species and subspecies

• All flamingos have black flight feathers, and wing coverts that are darker pink that the body.
• American: the brightest overall color, knees darker pink; beak deep pink, lower bill darker.
• Greater: similar in size to American, but body, neck and head very pale pink;  knees with less contrasting color; bill with less black, the rest a light pink. Distribution- Africa, Mediterranean, Middle East, Southern Russia, India.
• Lesser: smallest; pale pink, but not as pale as Greater; slight spotting of darker pink on back;  entire bill dark red, almost black, all the way to the eye; legs dark gray/pink w/o contrasting knee color. Distribution-  mostly southeastern Africa with outlying populations in western Africa, the middle east, and India.
• Chilean: very similar to the Greater, but slightly smaller; during breeding, breast and neck may become slightly more pink; legs yellow-gray with contrasting dark pink knees and feet; bill tip black, base is very pale pink. Distribution- southwestern South America in Peru, Bolivia, Chile and Argentina from lowlands to high altitude lakes.
• Andean: similar to Chilean, but head and neck a truer pink than other flamingos (more pink than orange/pink), which extends to spotting on the breast; legs bright yellow with no contrasting knees; bill with black tip and yellow base. Distribution- small area of the Andean Altiplano at 3500 - 4500 m (11,500 ft-14,800 ft); overlaps with Chilean and James'.
• James's: very similar to Chilean and Andean, but smaller than both; when breeding, has band of dark pink spots on the breast; legs dark pink without contrasting knees; bill tip black, basal 2/3 is a dark yellow which is lined with red along the proximal edge and around the eye. Distribution- high elevation (usually greater than 4000 m) salt flats in Peru, Bolivia, Chile and Argentina; range overlaps the other two South American species' ranges, but much more restricted.

del Hoyo et al. (1992)
Fox (1975)
Ogilvie & Ogilvie (1986)
Rooth (1965)
Shannon (2000)
Zweers et al. (1995)