Red-billed Gull

Red-billed 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. scopulinus
Binomial name
Chroicocephalus scopulinus (Forster, 1844)
Synonyms
Larus novaehollandiae scopulinus, Larus scopulinus

The Red-billed Gull (Chroicocephalus scopulinus), once also known as the Mackerel Gull, is a native of New Zealand, being found throughout the country and on outlying islands including the Chatham Islands and Sub-antarctic islands.The Māori name of this species is Tarapunga or Akiaki.^[2] Its vernacular name is sometimes also used for the Dolphin Gull, a somewhat similar-looking but unrelated species. As is the case with many gulls, the Red-billed Gull has traditionally been placed in the genus Larus.

Description

Upper body

The Red-billed Gull is a fairly small gull with an all-red bill, red eye ring, red legs and feet, pale grey wings with black wingtips. The rest of the body and tail are white. There is virtually no visual difference between the male and female birds. The immature gulls have a dark brown bill with only hints of red. The legs are also brown and there are brown spots on the grey wings.

Distribution

It is the smallest gull commonly seen in New Zealand; a recent estimate of the population puts it at half a million birds in the country. Until recently it was regarded as a subspecies of the Silver Gull Larus novaehollandiae found in Australia, and the two species are very similar in appearance. However the most recent research suggests that they are not particularly closely related.^[3]

Behaviour

Vocalisations by two Red-billed Gulls

Behaviourally, the Red-Billed Gull is a typical gull. It is an aggressive scavenger and kleptoparasite. Since European settlement its numbers have increased, especially around coastal towns and cities where it can scavenge from urban waste. It normally feeds on small fish, shell fish and worms (from pastures), and sometimes berries, lizards and insects.

Life cycle

They nest from October to December in colonies on the coast, either on islands or rocky headlands, cliffs and beaches. The birds form pair bonds which endure across seasons, but there is a certain amount of extra-pair copulation. Courtship feeding is an important part of the preparation for mating. Nests are well formed and may be constructed of seaweed, grasses, leaves and ice plants. Generally two to three eggs are laid, their colour ranges from brown to grey with light and dark brown spots all over.

Gallery

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  Comparison of adult (left) and immature (right) Red-billed Gulls in flight

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  Second-winter, first-winter, and adult birds (first three, from front)

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  Red-billed Gull in flight

References

1. ^ BirdLife International (2004). Larus scopulinus. 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. ^ Barrie Heather and Hugh Roberston (2005). The Field Guide to the Birds of New Zealand (revised edition). Viking. 
3. ^ Shirihai, H. (2002). A complete guide to Antarctic wildlife. Alula Press, Oy, Finland. 

• Mills, J. A. (1994). Extra-pair copulations in the Red-Billed Gull: Females with high-quality, attentive males resist. Behaviour, 128, 41-64.
• 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
• Tasker, C. R., & Mills, J. A. (1981). A functional analysis of courtship feeding in the Red-billed Gull, Larus Novaehollandiae scopulinus. Behaviour, 77, 222ff

External links

• Media related to Larus scopulinus at Wikimedia Commons