Silver Gull

Silver Gull
Adult
Conservation status
Least Concern (IUCN 3.1)[1]
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. gunni Mathews 1912 C. n. novaehollandiae (Stephens, 1826)
Synonyms
Larus novaehollandiae

The Silver Gull (Chroicocephalus novaehollandiae) also known simply as "seagull" in Australia, is the most common gull seen in Australia. It has been found throughout the continent, but particularly coastal areas. The South African Hartlaub's Gull (C. hartlaubii) and the New Zealand Red-billed Gull (C. scopulinus) were 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.

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.

The Silver Gull has a sharp voice consisting of a variety of calls. "The most common call is a harsh 'kwee-aarr'."^[2]

Description

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 wing span 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

Adult in Tasmania

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 USA; one bird was shot in August 1947 at the mouth of the Genessee River, Lake Ontario and another one was photographed in Salem County, New Jersey, in autumn 1996. Both are nowadays believed to have escaped from captivity (AOU, 2000).

Behaviour

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 1–3 eggs.^[3][4]

Various views and plumages

• 

  Juvenile (first winter)

• 

  a silver gull in Circular Quay railway station, Sydney

• 

  Immature, in flight

• 

  Adult, in flight

• 

  Bathing

• 

  Keeping an eye out for a free lunch

Off Gold Coast, Australia

References

1. ^ BirdLife International (2004). Larus novaehollandiae. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 11 May 2006. Database entry includes justification for why this species is of least concern
2. ^ Silver Gull, Birds in Backyards
3. ^ ^{a b c} "Silver Gull". Birds in Backyards, Australian Museum. 23-Jan-07. http://www.birdsinbackyards.net/finder/display.cfm?id=95. Retrieved 2009-05-10. 
4. ^ ^{a b c d e f} Pizzey, Graham; Knight, Frank (1997). Field Guide to the Birds of Australia. Sydney, Australia: HarperCollinsPublishers. p. 111. ISBN 0 207 18013 X. 

• American Ornithologists' Union (AOU) (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

• 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