The American flamingo (Phoenicopterus ruber) is a large species of flamingo native to the West Indies, northern South America (including the Galápagos Islands) and the Yucatan Peninsula. It is closely related to the greater flamingo and Chilean flamingo, and was formerly considered conspecific with the greater flamingo, but that treatment is now widely viewed (e.g. by the American and British Ornithologists' Unions) as incorrect due to a lack of evidence. It is also known as the Caribbean flamingo, although it is also present in the Galápagos Islands. It is the only flamingo that naturally inhabits North America.
It is a cultural icon for the U.S. state of Florida, where it was formerly abundant in the southernmost regions, although it was largely extirpated by 1900 and is now only an uncommon visitor with a few small, potential resident populations.
The American flamingo breeds in South America (in the Galápagos Islands of Ecuador, coastal Colombia and Venezuela, and northern Brazil), in the West Indies (Trinidad and Tobago, Cuba, Jamaica, Hispaniola (the Dominican Republic and Haiti), The Bahamas, the Virgin Islands, and the Turks and Caicos Islands), and tropical and subtropical areas of continental North America (along the northern coast of the Yucatán Peninsula in Mexico, and formerly southern Florida in the United States). It is a vagrant to Puerto Rico, Anguilla, Barbados, Honduras, and (following its extirpation) Florida, although some Florida populations are now thought to be year-round residents. The population in the Galápagos Islands differs genetically from that in the Caribbean; the Galápagos flamingos are significantly smaller, exhibit sexual dimorphism in body shape, and lay smaller eggs. They are sometimes separated as Phoenicopterus ruber glyphorhynchus.
Its preferred habitats are similar to those of its relatives: saline lagoons, mudflats, and shallow, brackish coastal or inland lakes. An example habitat is the Petenes mangroves ecoregion of the Yucatán.
Like other flamingo species, American flamingos will migrate short distances to ensure that they get enough food or because their current habitat has been disturbed in some way. One habitat disturbance that has been observed to cause flamingos to leave their feeding grounds is elevated water levels. These conditions make it difficult for Phoenicopterus ruber to wade, hindering their ability to access food. The flamingos will then abandon their feeding grounds in search of an alternate food source. While the flights are not as long as other migratory birds, flamingos still fly for periods without eating.
Mating and bonding behaviors of P. ruber individuals have been extensively studied in captivity. The American flamingo is usually monogamous when selecting a nest site, and incubating and raising young; however, extra-pair copulations are frequent.
While males usually initiate courtship, females control the process. If interest is mutual, a female walks by the male, and if the male is receptive, he walks with her. Both parties make synchronized movements until one member aborts this process. For low-intensity courtships, males and females walk in unison with their heads raised. In high-intensity courtships, males and females walk at a quick pace with their heads dropped in a false feeding posture. This high-intensity courtship stops at any point if either bird turns and the other does not follow, the heads are raised, unison movements are stopped, or the pace of movement is slowed. If the female is ultimately receptive to copulation, she stops walking and presents for the male. Long-term pairs do not frequently engage in courtship behaviors or in-group display. Pairs often stand, sleep, and eat in close proximity.
Courtship is most often seen among individuals that change partners often or are promiscuous. A spectrum of pairing relationships is seen. Some birds have a long-term partner throughout the year; others form pairs during periods of courtship and nest attendance. How long a relationship lasts is affected by many factors, including addition and removal of adults, maturation of juveniles, and occurrence of trios and quartets. In most pairs, both individuals usually construct and defend the nest site. In rare cases, one individual undertakes both duties. Within trios, the dominant pair begins the nesting process by choosing and then defending the site.