Pacific gull

Larus pacificus Latham, 1802

Order: Charadriiformes

Family: Laridae

New Zealand status: Native

Conservation status: Vagrant

Other names: jack gull, Australian gull, large-billed gull, larger gull, mollyhawk

Geographical variation: Two subspecies, pacificus SE Australia, georgii South Australia & Western Australia.

Pacific gull. Adult. Woolamai Beach, Phillip Island, Victoria, Australia, February 2013. Image © Simon Smith by Simon Smith

Pacific gull. Adult. Woolamai Beach, Phillip Island, Victoria, Australia, February 2013. Image © Simon Smith by Simon Smith

Endemic to southern and south-western Australia, the Pacific gull is the largest gull in the Australian, New Zealand and Antarctic region, and has the largest bill of any gull in the world. In Australia it is under threat from the more versatile southern black-backed gull, which after self-introducing from about the 1940s, is rapidly expanding its breeding range in Tasmania and south-eastern Australia. The eastern subspecies possibly numbers no more than 1,100 breeding pairs, whereas the population of the western subspecies georgii, is considered secure. Pacific gulls are well known for taking molluscs (e.g. limpets, turban shells, mussels), flying to some height over rocks and then dropping them to smash the shells open. Sometimes, however, the gull will fly down and catch the shell before hitting the ground, and there is some debate as to whether the practice is primarily one of food gathering or play.

Identification

A large black-and-white gull, significantly larger than southern black-backed gull, although overall similar in general appearance. When compared to the southern black-backed gull, the Pacific gull has a massive bill with a prominent ‘gonys’ (angular bend near the tip of the lower mandible) and rounded nostrils. In adults, the red tip to the bill is on both the upper and lower mandibles (southern black-backed gull has a red spot only on the lower mandible), and the tail of an adult Pacific gull has a broad dark sub-terminal band, clearly visible in flight. There is less white on the wings of an adult Pacific gull, apparent both at rest and in flight.

Voice: a shouted ‘ow-ow’ which can be quite long, also short ‘oh-oh’, throaty ‘cark-cark’ or ‘auk-auk’, chuckles and stutters. Quite different in character to southern black-backed gull calls.

Similar species: southern black-backed gull.

Distribution and habitat

The southern and west coasts of Australia from as far north as Sydney in the east to Shark Bay in the west. Ironically, it is rare on the Pacific (east) coast of mainland Australia, with its strongholds being Bass Strait, Tasmania, Kangaroo Island, Recherche Archipelago, Houtman Abrolhos and Shark Bay. Much less an urban bird, and less adaptable than the southern black-backed gull, the Pacific gull favours sandy and rocky coasts. In eastern Australia it prefers more sheltered environments, away from ocean swells, but in the west it prefers exposed situations.

New Zealand records

The only New Zealand record was an immature bird at Glinks Gully, Dargaville Beach in January 2010.

Behaviour and ecology

Pacific gulls can often be found loafing or roosting high up on rocky cliffs, or man-made structures such as jetties, pylons and wharves. They nest on offshore islands, either as isolated pairs or small colonies. Both sexes build the nest, which can either be a well-formed bowl of collected material, or an unlined or lined scrape in the ground. Two or three mottled brown eggs are laid.

Food

A carnivore with a wide-ranging diet, the Pacific gull will hunt or scavenge as the opportunity presents itself. Known to hunt a number of bird species, both during the day and at night, up to the size of short-tailed shearwater. Pacific gulls are capable of swallowing quite large prey items whole. They also steal fish from fishing birds such as gannets, scavenge offal from fishermen, prise molluscs from rocks, eat beachcast carrion, and consume fur seal vomit and placentae. Food also includes crabs, squid, worms, echinoderms and chitons.

Weblinks

http://ibc.lynxeds.com/species/pacific-gull-larus-pacificus

http://www.birdlife.org.au/bird-profile/pacific-gull

References

del Hoyo, J.; Elliott, A.; Sargatal, J. (eds) 1996. Handbook of the birds of the world. Vol. 3. Hoatzins to Auks. Lynx Edicions, Barcelona.

Enticott, J.; Tipling, D. 1997. Photographic handbook of the seabirds of the world. New Holland, London.

Higgins, P.J.; Davies, S.J.J.F. (eds.) 1996. Handbook of Australian, New Zealand and Antarctic birds. Vol. 3. Snipe to Pigeons. Oxford University Press, Melbourne.

Miskelly, C.M.; Crossland, A.C.; Sagar, P.M.; Saville, I.; Tennyson, A.J.D.; Bell, E.A. 2013. Vagrant and extra-limital bird records accepted by the OSNZ Records Appraisal Committee 2011-2012. Notornis 60: 296-306.

Pizzey, G.; Knight, F.; Pizzey, S. 2012. The field guide to the birds of Australia (9th edn). HarperCollins, Australia.

Slater, P.; Slater, P.; Slater, R. 1989. The Slater field guide to Australian birds (revised edn). Lansdowne, Sydney.

Recommended citation

Griffin, P. 2013. Pacific gull. In Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz

Pacific gull

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