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Species Evolution 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 is as follows: Classification The identity of the closest relatives of the flamingos has long been somewhat mysterious. Traditionally, the long-legged Ciconiiformes, probably a paraphyletic assemblage, have been considered the flamingo's 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 were considered as well (Sibley et al., 1969). To reflect the uncertainty about this matter, flamingos began to be placed in their own order later on. Some scientists proposed flamingos as waders most closely related to the stilts and avocets, Recurvirostridae. In recent years, DNA-studies have had unsuspected results: Sibley & Monroe placed flamingos within the expanded (and certainly paraphyletic, as later turned out) Ciconiiformes. Since long, it has been the grebes (Podicipedidae) rather then long-legged waders, ducks or stilts, that were time and again indicated as the closest relatives of flamingos, and there is currently renewed interest in this hypothesis. Whether the two families would be placed in an order together or retained as different orders is uncertain at the moment, however. In a 2005 study, the Neognathae, consisting of all living birds except the ratites, tinamous, 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 paraphyletic 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. All of this shows that firm agreement about the exact relationships of flamingos is still not reached. 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, both when feeding and at rest. The reason for this behavior 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. Color
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. Threat 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. Footnotes | |||||||||||||||||||||||||||||||||||
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