Information about Common Gull

Common Gull
Common Gull Larus canus canus, Finland Common Gull Larus canus canus, Finland
Conservation status
Least Concern
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Aves Order: Charadriiformes Family: Laridae Genus: Larus Species: L. canus
Binomial name
Larus canus Linnaeus, 1758, Sweden

The Common Gull or Mew Gull (Larus canus) is a medium-sized gull which breeds in northern Asia, northern Europe and northwestern North America. It migrates further south in winter.^[1]

Adults are 40-46 cm long, obviously smaller than the Herring Gull, and slightly smaller than the Ring-billed Gull, also differing from this in its shorter, more tapered bill with a more greenish shade of yellow, as well as being unmarked during the breeding season. The body is grey above and white below. The legs are greenish-yellow. In winter, the head is streaked grey, and the bill often has a poorly-defined blackish band near the tip (sometimes sufficiently obvious to cause confusion with Ring-billed Gull). They have black wingtips with large white "mirrors". Young birds have scaly black-brown upperparts and a neat wing pattern, and grey legs. They take two to three years to reach maturity. The call is a high-pitched "laughing" cry.^[1][2]

Taxonomy

There are four subspecies, two of them considered distinct species by some authorities:^[1][3]

• Larus canus canus Linnaeus, 1758. Common Gull. Europe and western Asia. Small; mantle medium grey (palest subspecies); wingtips with extensive black; iris dark. Wingspan 110-125 cm; weight 290-480 g.
• Larus canus heinei Homeyer, 1853. Central northern Asia. Medium size; mantle dark grey (darkest subspecies); wingtips with extensive black; iris dark. Weight 315-550 g.
• Larus canus kamschatschensis (Bonaparte, 1857); syn. L. kamschatschensis. "Kamchatka Gull". Northeastern Asia. Large; mantle medium-dark grey; wingtips with extensive black; iris pale. Weight 394-586 g.
• Larus canus brachyrhynchus Richardson, 1831; syn. L. brachyrhynchus. Mew Gull or "Short-billed Gull". Alaska and western Canada. Small; mantle medium-dark grey; wingtips with little black and much white; iris pale. Wingspan 96-102 cm; weight 320-550 g.

Ecology

Both Common and Mew Gulls breed colonially near water or in marshes, making a lined nest on the ground or in a small tree; colony size varies from two to 320 or more pairs. Usually three eggs are laid (sometimes just one or two); they hatch after 24-26 days, with the chicks fledging after a further 30-35 days. Like most gulls, they are omnivores and will scavenge as well as hunt small prey. The global population is estimated to be about one million pairs; they are most numerous in Europe, with over half (possibly as much as 80-90%) of the world population.^[4] By contrast, the Alaskan population is only about 10,000 pairs.^[1]

Vagrancy

The Common Gull occurs as a scarce winter visitor to coastal eastern Canada and as a vagrant to the northeastern USA,^[5] and there is one recent record of Mew Gull in Europe on the Azores.^[6]

<gallery widths="250px" heights="225px" perrow="2"> Image:Larus_canus1.jpg|Adult Mew Gull. Anchorage Coastal Wildlife Refuge, Alaska. Image:LarusCanus.non-breeding plumage.jpg|Common Gull in winter plumage. Tallinn, Estonia. </gallery>

References

• BirdLife International (2004). Larus canus. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 11 May 2006. Database entry includes justification for why this species is of least concern
• "National Geographic" Field Guide to the Birds of North America ISBN 0-7922-6877-6
• Seabirds, an Identification Guide by Peter Harrison, (1983) ISBN 0-7470-1410-8