Pelicans (genus Pelecanus) are a genus of large water birds that make<!-- "pelicans" is the subject --> up the family Pelecanidae. They are characterized by a long beak and a large throat pouch used for catching prey and draining water from the scooped-up contents before swallowing. They have predominantly pale plumage, except for the brown and Peruvian pelicans. The bills, pouches, and bare facial skin of all pelicans become brightly coloured before the breeding season.
The eight living pelican species have a patchy, seasonally-dependent yet global distribution, ranging latitudinally from the tropics to the temperate zone. Pelicans are absent from interior Amazonian South America, from polar regions and the open ocean; at least one species is known to migrate to the inland desert of Australia's Red Centre, after heavy rains create temporary lakes. White pelicans are also observed at the American state of Utah's Great Salt Lake, for example, some 600 miles (965 km) from the nearest coastline (the Pacific West Coast). They have also been seen hundreds of miles inland in North America, having flown northwards along the Mississippi River and other large waterways.
Long thought to be related to frigatebirds, cormorants, tropicbirds, and gannets and boobies, pelicans instead are most closely related to the shoebill and hamerkop storks (although these two birds are not actually true storks), and are placed in the order Pelecaniformes. Ibises, spoonbills, herons, and bitterns have been classified in the same order. Fossil evidence of pelicans dates back at least 36 million years to the remains of a tibiotarsus recovered from late Eocene strata of Egypt that bears striking similarity to modern species of pelican. They are thought to have evolved in the Old World and spread into the Americas; this is reflected in the relationships within the genus as the eight species divide into Old World and New World lineages. This hypothesis is supported by fossil evidence from the oldest pelican taxa. which is itself derived from the word pelekys (πέλεκυς) meaning "axe". In classical times, the word was applied to both the pelican and the woodpecker.
Taxonomy history
The genus Pelecanus was first formally described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae. He described the distinguishing characteristics as a straight bill hooked at the tip, linear nostrils, a bare face, and fully webbed feet. This early definition included frigatebirds, cormorants, and sulids, as well as pelicans. The family Pelecanidae was later introduced (as Pelicanea) by the French polymath Constantine Samuel Rafinesque in 1815.
Order and related taxa
Pelicans give their name to the Pelecaniformes, an order which has undergone significant revision. Tropicbirds (now Phaethontiformes), darters, cormorants, gannets, boobies, and frigatebirds (now Suliformes), all traditional members of the order, have since been removed from Pelecaniformes. In their place, herons, ibises, spoonbills, the hamerkop, and the shoebill have now been added into the Pelecaniformes. Together, they form a distinct clade within Pelecaniformes, although their precise evolutionary relationships remain under study.
{|
|-
| style="vertical-align:top;"|
Cladogram based on Hackett et al. (2008).
|style="vertical-align:top;"|
|}
Evolution and fossil record
The oldest known pelican fossil is Eopelecanus aegyptiacus, a tibiotarsus from the late Eocene (Priabonian) the Birket Qarun Formation in the Wadi El Hitan in Egypt (~36 million years ago). It shows striking similarities with modern species. Both fossils show a beak nearly morphologically identical to that of present-day pelicans. Frass,1870; P. gracilis, Milne-Edwards, 1863; P. odessanus, Widhalm, 1886
- North America: P. halieus, Wetmore, 1933; P. schreiberi, Olson, 1999
- Asia: P. cautleyi, Davies, 1880; P. sivalensis, Davies, 1880
- Australia: P. cadimurka, Rich & van Tets, 1981; P. tirarensis, Miller, 1966
Controversial and dubious fossil assignments
- Protopelicanus (Late Eocene) – Once considered a possible early pelecaniform, this bird might instead belong to the Pelagornithidae (pseudotooth birds) or another unrelated aquatic lineage. It is not generally accepted as a member of Pelecanidae.