Gull

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Gulls
Black-headed Gull
Scientific classification
Kingdom:
Phylum:
Class:
Order:
Suborder:
Family:
Laridae

Vigors, 1825
Genera

Larus
Rissa
Pagophila
Rhodostethia
Xema
Creagus

Gulls (often informally Seagulls) are birds in the family Laridae. They are most closely related to the terns (family Sternidae) and only distantly related to auks, and skimmers, and more distantly to the waders. Most gulls belong to the large genus Larus.

They are typically medium to large birds, usually grey or white, often with black markings on the head or wings. They have stout, longish bills, and webbed feet. Gull species range in size from the Little Gull, at 120 g (4.2 oz) and 29 cm (11.5 inches), to the Great Black-backed Gull, at 1.75 kg (3.8 lbs) and 76 cm (30 inches).

Most gulls, particularly Larus species, are ground nesting carnivores, which will take live food or scavenge opportunistically. The live food often includes crabs and small fish. Apart from the kittiwakes, gulls are typically coastal or inland species, rarely venturing far out to sea. The large species take up to four years to attain full adult plumage, but two years is typical for small gulls.

Gulls — the larger species in particular — are resourceful and highly-intelligent birds, demonstrating complex methods of communication and a highly-developed social structure - for example many gull colonies display mobbing behaviour, attacking and harassing would-be predators and other intruders.[1] In addition, certain species (e.g. the Herring Gull) have exhibited tool use behaviour. Many species of gull have learned to co-exist successfully with man and have thrived in human habitats. Others rely on kleptoparasitism to get their food.

Two terms are in common usage among gull enthusiasts for subgroupings of the gulls:

Hybridisation between species of gull occurs quite frequently, although to varying degrees depending on the species involved (see Hybridisation in gulls). The taxonomy of the large white-headed gulls is particularly complicated.

In common usage, members of various gull species are often referred to as sea gulls or seagulls. This name is used by the layman to refer to a common local species or all gulls in general, and has no fixed taxonomic meaning.

Gulls can be aggressive
A gull hovers
File:Gull is eating a crayfish 2.jpg
A gull eating a crayfish

The American Ornithologists' Union combines Sternidae, Stercorariidae, and Rhynchopidae as subfamilies in the family Laridae, but recent research [2] [3] [4] indicates that this is incorrect.


List of gulls in taxonomic order

A gull is attacking a coot

Genus Larus

Genus Rissa

Genus Pagophila

Genus Rhodostethia

Genus Xema

Genus Creagrus

The Laridae are known from fossil evidence since the Early Oligocene, some 30-33 mya. A fossil gull from the Middle to Late Miocene of Cherry County, USA is placed in the prehistoric genus Gaviota; apart from this and the undescribed Early Oligocene fossil, all prehistoric species were tentatively assigned to the modern genus Larus. Among those of them that have been confirmed as gulls, "Larus" elegans and "L." totanoides from the Late Oligocene/Early Miocene of SE France have since been separated in Laricola.

Gallery

References

  1. ^ Alcock, J. (1998) Animal Behavior: An Evolutionary Approach (6th edition). Sinauer Associates, Inc. Sunderland, Massachusetts. ISBN 0-87893-009-4
  2. ^ Paton, Tara A. & Baker, Allan J. (2006): Sequences from 14 mitochondrial genes provide a well-supported phylogeny of the Charadriiform birds congruent with the nuclear RAG-1 tree. Molecular Phylogenetics and Evolution 39(3): 657–667. doi:10.1016/j.ympev.2006.01.011 (HTML abstract)
  3. ^ Paton, T. A.; Baker, A. J.; Groth, J. G. & Barrowclough, G. F. (2003): RAG-1 sequences resolve phylogenetic relationships within charadriiform birds. Molecular Phylogenetics and Evolution 29: 268-278. doi:10.1016/S1055-7903(03)00098-8 (HTML abstract)
  4. ^ Thomas, Gavin H.; Wills, Matthew A. & Székely, Tamás (2004): A supertree approach to shorebird phylogeny. BMC Evol. Biol. 4: 28. doi:10.1186/1471-2148-4-28 PDF fulltext Supplementary Material

Bibliography

  • Grant, Peter J. (1986) Gulls: a guide to identification ISBN 0-85661-044-5
  • Howell, Steve N. G. and Jon Dunn (2007) Gulls of the Americas ISBN 0-618-72641-1
  • Olsen, Klaus Malling & Larsson, Hans (1995): Terns of Europe and North America. Christopher Helm, London. ISBN 0-7136-4056-1

External links