Flamingo

2007 Schools Wikipedia Selection. Related subjects: Birds

iFlamingos
A Caribbean Flamingo (Phoenicopterus ruber), with Chilean Flamingos (P. chilensis) in the background
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Aves Order: Phoenicopteriformes Fürbringer, 1888 Family: Phoenicopteridae Bonaparte, 1831 Genus: Phoenicopterus Linnaeus, 1758

Flamingos are gregarious wading birds in the genus Phoenicopterus and family Phoenicopteridae. They are found in both the Western and Eastern Hemispheres, but are more numerous in the latter. There are four species in the Americas while two exist in the Old World. A group of flamingos is called a "pat".

Systematics

Species

Evolution

Lesser Flamingos in the Ngorongoro Crater, Tanzania

The prehistory of the Phoenicopteriformes is far better researched than their systematic affinities (see below). An extinct family of peculiar "swimming flamingos", the Palaelodidae, was initially believed to be the ancestors of the Phoenicopteridae. This is nowadays rejected, as the fossil genus Elornis, apparently a true albeit primitive flamingo, is known from the Late Eocene, before any palaelodid flamingos have been recorded. A considerable number of little-known birds from the Late Cretaceous onwards are sometimes considered to be flamingo ancestors. These include the genera Torotix, Parascaniornis, Scaniornis, Gallornis, Agnopterus, Juncitarsus and Kashinia; the latter two are probably proto-flamingos, while the relationships of the others are not clear at present.

There exists a fairly comprehensive fossil record of the genus Phoenicopterus. The systematics of prehistoric Phoenicopteriformes known only from fossils is as follows:

• Placement unresolved
  • Phoeniconotius (Etadunna Late Oligocene/Early Miocene of Lake Pitikanta, Australia)

• Palaelodidae
  • Adelalopus (Borgloon Early Oligocene of Hoogbutsel, Belgium)
  • Palaelodus (Middle Oligocene -? Middle Pleistocene)
  • Megapaloelodus (Late Oligocene - Early Pliocene)

• Phoenicopteridae
  • Elornis (Late Eocene - Early Oligocene)
  • Prehistoric species of
    • Phoenicopterus croizeti (Middle Oligocene - Middle Miocene of C Europe)
    • Phoenicopterus floridanus (Early Pliocene of Florida)
    • Phoenicopterus stocki (Middle Pliocene of Rincón, Mexico)
    • Phoenicopterus copei (Late Pleistocene of W North America and C Mexico)
    • Phoenicopterus minutus (Late Pleistocene of California, USA)
    • Phoenicopterus aethiopicus

Relationships

The identity of the closest relatives of the flamingos is a rather contentious issue. Traditionally, the long-legged Ciconiiformes, probably a paraphyletic assemblage, have been considered the flamingos' closest relatives and the family was included in the order. Usually the spoonbills and ibises of the Threskiornithidae were considered their closest relatives within this order. Nevertheless, relationships to the Anseriformes (waterfowl) were considered as well (Sibley et al., 1969), especially as flamingos and waterfowl are parasitized by closely-related feather lice.

To reflect the uncertainty about this matter, flamingos began to be placed in their own order later on. Other scientists proposed flamingos as waders most closely related to the stilts and avocets, Recurvirostridae.

In recent years, molecular studies have yielded unexpected results: Sibley & Monroe placed flamingos within the expanded (and certainly paraphyletic, as is now known) Ciconiiformes. On the other hand, since long it has been the grebes ( Podicipedidae), rather than Ciconiiformes, ducks, or stilts, that were time and again indicated as the closest relatives of flamingos, and there is currently renewed interest in this hypothesis.

In a 2004 study comparing DNA sequences of intron 7 of the β- fibrinogen gene (FGB-int7), the Neognathae (all living birds except the ratites and tinamous) excluding waterfowl and Galliformes were shown to be divided into two subgroups of uneven size. The first and smaller one, Metaves, contains flamingos and grebes, alongside the hoatzin, pigeons, sandgrouse, the Caprimulgiformes, the Apodiformes, tropicbirds, mesites, sunbittern and kagu. Interestingly, most of these groups have traditionally been difficult to place on the family tree of birds. According to this study, all other birds belong to the second subgroup of Neoaves, the Coronaves (Fain & Houde, 2004). But their molecular data was insufficient to resolve inter-Metaves relationships to satisfaction; the flamingo FGB-int7 sequence is apparently most similar to that of some species of nighthawks, strongly suggesting a case of convergent evolution on the molecular level. The conclusions that one can draw from this study are twofold: first, that flamingos are Metaves, and second, that FBG-int7 is unsuitable to determine their relationships beyond that. It is interesting to note, however, that among all the groups which have been proposed as sister taxa of the flamingos, only the grebes are Metaves.

In conclusion, the relationships of the flamingos still cannot be resolved with any certainty, but presently a close relationship with grebes appears somewhat likelier than other proposals. Still, all this confusion serves to show that all lines of "evidence" - molecular, morphological, ecological and parasitological - are liable to yield erroneous "proof" and that no method can be considered generally superior. Any future attempt to finally resolve the flamingos' relationships, therefore, would have to employ multiple independent lines of evidence to support it and carefully weigh these against alternative proposals.

Physiology

Lesser Flamingos in flight

Diet

Flamingos filter-feed on shellfish and algae. Their oddly-shaped beaks are specially adapted to separate mud and silt from the food they consume, and are uniquely used upside-down. The filtering of food items is assisted by hairy structures called lamellae which line the mandibles, and the large rough-surfaced tongue. It is the shellfish and shrimps which flamingos eat which give them their distinctive pink colour, otherwise they would be white.

Legs

Flamingos frequently stand on one leg. The reason for this behaviour is not fully known. One common theory is that tucking one leg beneath the body may conserve body heat, but this has not been proven. In addition to standing in the water, flamingos may stamp their webbed feet in the mud to stir up food from the bottom.

Colour

Young flamingos hatch with grey plumage, but the feathers of an adult range from light pink to bright red, due to carotenoids obtained from their food supply. A flamingo that is well fed and healthy is vibrantly coloured bright pink or red. The pinker a flamingo is, the more desirable it is as a mate. A white or pale flamingo, however, is usually unhealthy or suffering from a lack of food. Notable exceptions are the flamingos in captivity, many of which turned a pale pink as they are not fed foods containing sufficient amounts of carotene. This is changing as more zoos begin to add shrimp and other supplements to the diets of their flamingos. All flamingos have 12 black flight feathers in each wing.

Feeding

Flamingos produce a “milk” like pigeon milk due to the action of a hormone called prolactin (see Columbidae). It contains more fat and less protein than the latter does, and it is produced in glands lining the whole of the upper digestive tract, not just the crop. Both parents nurse their chick, and young flamingos feed on this milk, which also contains red and white blood cells, for about two months until their bills are developed enough to filter feed.

Conservation status

Flamingos in the Jerusalem Biblical Zoo

Scientists have discovered that birds are dying in their thousands along the Rift Valley lakes of Kenya and Tanzania. However, they are baffled about the reason. Possible causes include avian cholera, botulism, metal pollution, pesticides or poisonous bacteria, say researchers. Also, fears for the future of the Lesser Flamingo — Phoeniconaias minor — have also been raised by plans to pipe water from one of their key breeding areas, the shores of Lake Natron. The lakes are crucial to the birds' breeding success because the flamingos feed off the blooms of cyanobacteria that thrive there.

Most scientific attention has focused on the environmental changes to the lakes. Water levels have lowered and concentrations of soda in the water have increased. This increases the risk of toxic bacteria growing there.