Gavia arctica

Gavia arctica, Photo: U.S. Fish and Wildlife Service

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: Gaviiformes
Familia: Gaviidae
Genus: Gavia
Species: Gavia arctica
Subspecies: G. a. arctica - G. a. viridigularis

Name

Gavia arctica (Linnaeus, 1758)

Vernacular names
Български: Черногуш гмуркач
Català: Calàbria agulla
Česky: Potáplice severní
Dansk: Sortstrubet lom
Deutsch: Prachttaucher
Ελληνικά : Λαμπροβούτι
English: Black-throated Diver, or Arctic Loon
Español: Colimbo ártico
Esperanto: Arkta kolimbo
Euskara: Aliota arktiko
Français: Plongeon arctique
Frysk: Bûnte Seedûker
Galego: Mobella ártica
Հայերեն: Սուզահավ սևախածի
Italiano: Strolaga mezzana
Lietuvių: Juodakaklis naras
Magyar: Sarki búvár
Nederlands: Parelduiker
日本語: オオハム
‪Norsk (bokmål)‬: Storlom
Polski: Nur czarnoszyi
Русский: Чернозобая гагара
Suomi: Kuikka
Svenska: Storlom
Türkçe: Kara gerdanlı dalgıç

The Black-throated Loon (Gavia arctica) is a migratory aquatic bird found in the northern hemisphere. The species is known as an Arctic Loon in North America and the Black-throated Diver in Eurasia, its current name is a compromise proposed by the International Ornithological Committee.[2]

Taxonomy

The Black-throated Loon was one of the many species originally described by Linnaeus in his 18th century work, Systema Naturae.[3] The genus name Gavia comes from the Latin for "sea mew", as used by ancient Roman naturalist Pliny the Elder.[4]

Description

Breeding adults are 63 to 75 cm in length with a 100 to 122 cm wingspan, shaped like a smaller, sleeker version of the Great Northern Diver. They have a grey head, black throat, white underparts and chequered black-and-white mantle. Non-breeding plumage is drabber with the chin and foreneck white. Its bill is grey or whitish and dagger-shaped. In all plumages a white flank patch distinguishes this species from all other divers including the otherwise almost identical Pacific Diver.

Distribution

It breeds in Eurasia and occasionally in western Alaska. It winters at sea, as well as on large lakes over a much wider range.

It is a vagrant to Pakistan


Behaviour

This species, like all divers, is a specialist fish-eater, catching its prey underwater. It flies with neck outstretched. It feeds on fish, insects, crustacens and amphibians.

The calls include a yodelling high-pitched wail and harsh growls, similar but lower pitched than Pacific Loon.

See Gaviidae for more details on general behaviour

Miscellaneous
Breeding and non-breeding Arctic Loons.

The Black-throated Diver is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.

Instructions for constructing and deploying artificial floating islands to provide Black-throated Divers with nesting opportunities are given in Hancock (2000).

On September 6, 2007, RSPB Scotland and the Scottish Natural Heritage (SNH) stated that it was surprised by an increase in the last 12 years in the breeding figures in the UK for the Red-throated Diver and the rarer Black-throated Diver of 16% and 34% respectively due to the anchoring of 58 man-made rafts in lochs. Both species decreased elsewhere in Europe.

The Black-throated Diver is the current school emblem of Achfary Primary School.

Dr Mark Eaton, RSPB scientist traced the drop in overall numbers to warming of the North Sea which reduced stocks of the fish on which they feed.[5]

References

^ BirdLife International (2008). Gavia arctica. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 2008-11-04.
^ Gill, F., Wright, M. & Donsker, D. (2009). IOC World Bird Names (version 2.2). Available at http://www.worldbirdnames.org/ Accessed 3 September 2009
^ (Latin) Linnaeus, Carl (1758). Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.. Holmiae. (Laurentii Salvii)..
^ Johnsgard, Paul A. (1987). Diving Birds of North America. University of Nevada–Lincoln. ISBN 0803225660.
^ BBC NEWS, Rise in divers mystifies experts

Hancock, Mark (2000). "Artificial floating islands for nesting Black-throated Divers Gavia arctica in Scotland: construction, use and effect on breeding success". Bird Study 47: 165–175. doi:10.1080/00063650009461172.HTML abstract
Peter (1988). Seabirds (2nd ed.). London: Christopher Helm. ISBN 0-7470-1410-8.
Field Guide to the Birds of North America. Washington DC: National Geographic Society. 2002. ISBN 0-7922-6877-6.


Identification

Appleby, R.H.; S. C. Madge and Killian Mullarney (1986). "Identification of divers in immature and winter plumages". British Birds 79 (8): 365–391.
Birch, A.; C.T. Lee (1997). "Field identification of Arctic and Pacific Loons". Birding 29: 106–115.
Birch, A.; C.T. Lee (1995). "Identification of the Pacific Diver - a potential vagrant to Europe". Birding World 8: 458–466.

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