Hellenica World

Larus cachinnans

Larus cachinnans (*)

Cladus: Eukaryota
Supergroup: Opisthokonta
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclassis: Tetrapoda
Classis: Aves
Subclassis: Carinatae
Infraclassis: Neornithes
Parvclassis: Neognathae
Ordo: Charadriiformes
Subordo: Lari
Familia: Laridae
Subfamilia: Larinae
Genus: Larus
Species: Larus cachinnans
Subspecies: L. c. cachinnans - L. c. ponticus

Name

Larus cachinnans Pallas, 1811

References

* Zoographia Rosso-Asiatica, 2 p.318

Vernacular names
Internationalization
Česky: Racek bělohlavý
Ελληνικά : Ασημόγλαρος της Κασπίας
English: Caspian Gull
Español: Gaviota patiamarilla
Français: Goéland pontique
Galego: Gaivota común
‪Norsk (bokmål)‬: Kaspimåke
Polski: Mewa białogłowa
Svenska: Kaspisk trut
Türkçe: Gümüş martı
Vèneto: Martinazzo

Caspian Gull is a name applied to the gull taxon Larus (argentatus) cachinnans, a member of the Herring Gull/Lesser Black-backed Gull complex.


Description

It is a large gull (59–67 cm, 680–1330 g) with a long, slender bill, accentuated by the sloping forehead. The legs, wings and neck are longer than those of the Herring Gull and Yellow-legged Gull. The eye is small and often dark, the legs vary from pale pink to a pale yellowish colour. The back and wings are a slightly darker shade of grey than the Herring Gull but slightly paler than the Yellow-legged Gull. The outermost primary feather has a large white tip and a white tongue running up the inner web.

First-winter birds have a pale head with dark streaking on the back of the neck. The underparts are pale and the back is greyish. The greater and median wing-coverts have whitish tips forming two pale lines across the wing.

Distribution

The Caspian Gull breeds around the Black and Caspian Seas, extending eastwards across Central Asia to north-west China. In Europe it has been spreading north and west and now breeds in Poland and eastern Germany. Some birds migrate south as far as the Red Sea and Persian Gulf while others disperse into Western Europe, in countries such as Sweden, Norway and Denmark. Small numbers are now seen regularly in Britain, especially in South-east England, East Anglia and the Midlands.

Breeding

It typically nests on flat, low-lying ground by water unlike the Yellow-legged Gull which mainly nests on cliffs in areas where the two overlap. The breeding season starts from early April. Two or three eggs are laid and incubated for 27 to 31 days.

Feeding

They are scavengers and predators with a very varied diet. During the breeding season they often eat rodents such as ground squirrels, flying some distance into the steppes to find them.

Classification and subspecies

This form has a troubled taxonomic history, summarised in the Herring Gull article. Currently, it is treated as a full species by some authorities and as a subspecies of the Herring Gull by others (e.g. the British Ornithologists' Union Records Committee). Some authorities include the Yellow-legged Gull (L. michahellis) within L. cachinnans but it is now commonly considered to be a separate species.

The Steppe Gull or Baraba Gull (L. (cachinnans) barabensis) may be regarded as a subspecies of the Caspian Gull or as a separate species. It is also very similar genetically to its northern neighbour, the taimyrensis race of Heuglin's Gull. The Steppe Gull breeds in Central Asia, particularly northern Kazakhstan. Its non-breeding range is still little-known but most are thought to winter in south-west Asia from the Persian Gulf to north-west India. There are possible records of this form from Hong Kong and South Korea.

The Mongolian Gull (L. (vegae/cachinnans) mongolicus) may be classed as a subspecies of the Caspian Gull, a subspecies of the East Siberian Gull or as a species in its own right. It breeds in Mongolia and surrounding areas and migrates south-east in winter.

*

References

* Paul Doherty & Bill Oddie (2001) Gulls: A Video Guide to the Gulls of Europe, Asia & North America. Videocassette. Bird Images.
* Dick Newell (2003) What is a Caspian Gull?. BirdGuides (http://www.birdguides.com/birdnews/articles.asp), accessed 18/9/06, subscription only.
* D.W. Snow & C.M. Perrins (1998) The Birds of the Western Palearctic, Concise Edition (Vol. 1), Oxford University Press, Oxford.


Further reading

Identification

* Garner & Quinn, British Birds 90:25-63, 369-84
* Bakker, Theo, Rudy Offereins and Rik Winters (2000) Caspian Gull identification gallery, Birding World 13(2): 60-74 (identification article including 34 images of Caspian Gulls of various ages)
* Neubauer, Gregory & Richard Millington (2000) Caspian Gull identification revisited Birding World 13(11): 462-5 (addresses identification in juvenile plumage)
* Small, Brian (2001) The juvenile Caspian Gull in Suffolk Birding World 14(9): 385-7
* Gibbins, Chris, Brian J. Small and John Sweeney (2010) From the Rarities Committee's files: Identification of Caspian Gull, part 1: typical birds British Birds 103(3): 142-183 (detailed identification paper, covering typical individuals)

Birds Images

Source: Wikipedia, Wikispecies: All text is available under the terms of the GNU Free Documentation License

Index

Scientific Library - Scientificlib.com