Red-billed gull

Red-billed gull
Adult
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 subantarctic 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. Juvenile gulls have a dark brown bill with only hints of red, making them difficult to distinguish from the black-billed gull. 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 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

Eating taupata berries

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. The bird generally lives up to 12 years, although individuals have also been found living up to 30 years.[4]

References

  1. ↑ BirdLife International (2004). "Larus scopulinus". IUCN Red List of Threatened Species. Version 2006. International Union for Conservation of Nature. Retrieved 11 May 2006. Database entry includes justification for why this species is of least concern
  2. ↑ Barrie Heather & Hugh Robertson (2005). The Field Guide to the Birds of New Zealand (revised ed.). Viking.
  3. ↑ Shirihai, H. (2002). A complete guide to Antarctic wildlife. Alula Press, Oy, Finland.
  4. ↑ Dangerfield, Emma (Dec 23, 2009). "Ex-pat Kiwi returns from US to study red-billed seagulls". Stuff.co.nz. Retrieved 2015-06-21.
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