Silver gull

Silver gull
Adult
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Class:Aves
Order:Charadriiformes
Family:Laridae
Genus:Chroicocephalus
Species: C. novaehollandiae
Binomial name
Chroicocephalus novaehollandiae
(Stephens, 1826)
Subspecies

C. n. forsteri (Mathews, 1912)
C. n. novaehollandiae (Stephens, 1826)

The silver gull (Chroicocephalus (Larus) novaehollandiae) is the most common gull seen in Australia. It has been found throughout the continent, but particularly at or near coastal areas.

It is smaller than the pacific gull, which is also found in Australia.

The silver gull should not be confused with the herring gull, which is called "silver gull" in many other languages (scientific name Larus argentatus, German Silbermöwe, French Goéland argenté, Dutch zilvermeeuw), but is a much larger, robust gull with no overlap in range.

Taxonomy

The South African Hartlaub's gull (C. hartlaubii) was formerly sometimes considered to be subspecies of the silver gull. As is the case with many gulls, it has traditionally been placed in the genus Larus, but is now placed in the genus Chroicocephalus.

There are three subspecies:[2]

  • C. n. forsteri (Mathews, 1912) - north and northeast Australia, New Caledonia, Loyalty Islands
  • C. n. novaehollandiae (Stephens, 1826) - southern Australia and Tasmania
  • C. n. scopulinus (Forster, JR, 1844) - New Zealand (red-billed gull)

Description

Juvenile (first winter)

The head, body, and tail are white. The wings are light grey with white-spotted, black tips.[3] Adults range from 40–45 cm in length.[3] Mean wingspan is 94 cm.[4] Juveniles have brown patterns on their wings, and a dark beak. Adults have bright red beaks—the brighter the red, the older the bird.

Distribution and habitat

Silver gulls are found in all states of Australia.[4] It is a common species, having adapted well to urban environments and thriving around shopping centres and garbage dumps.

Silver gulls have twice been recorded in the United States; one bird was shot in August 1947 at the mouth of the Genesee River, Lake Ontario, and another was photographed in Salem County, New Jersey, in autumn 1996. Both are now believed to have escaped from captivity.[5]

Behaviour

Egg and nestlings in nest at Phillip Island Nature Park, Victoria

The silver gull has a sharp voice consisting of a variety of calls. The most common call is a harsh, high pitched 'kwarwh'.[3]

Feeding

The silver gull naturally feeds on worms, fish, insects and crustaceans. It is a successful scavenger, allowing increased numbers near human settlements.

Breeding

Breeding occurs from August to December.[4] The nest is located on the ground and consists of seaweed, roots, and plant stems.[4] The nests may be found in low shrubs, rocks and jetties.[4] Typical clutch size is one to three eggs.[3][4]

Various views and plumages

References

  1. ↑ BirdLife International (2012). "Larus novaehollandiae". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
  2. ↑ Gill, Frank; Donsker, David, eds. (2017). "Coursers, noddies, gulls, terns, auks & sandgrouse". World Bird List Version 7.2. International Ornithologists' Union. Retrieved 21 April 2017.
  3. 1 2 3 4 "Silver Gull". Birds in Backyards, Australian Museum. 2007-01-23. Archived from the original on 2010-04-13. Retrieved 2009-05-10.
  4. 1 2 3 4 5 6 Pizzey, Graham; Knight, Frank (1997). Field Guide to the Birds of Australia. Sydney, Australia: HarperCollinsPublishers. p. 111. ISBN 0-207-18013-X.
  5. ↑
    • American Ornithologists' Union (2000): Forty-second supplement to the American Ornithologists' Union Check-list of North American Birds. Auk 117(3): 847–858. DOI: 10.1642/0004-8038(2000)117[0847:FSSTTA]2.0.CO;2.

Further reading

  • Harrison, Peter (1988): Seabirds (2nd ed.). Christopher Helm, London. ISBN 0-7470-1410-8
  • Pons J.M., Hassanin, A., and Crochet P.A.(2005). Phylogenetic relationships within the Laridae (Charadriiformes: Aves) inferred from mitochondrial markers. Molecular Phylogenetics and Evolution 37(3):686-699
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