Common gull
| Common gull | |
|---|---|
 |
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| Adult mew gull. Anchorage Coastal Wildlife Refuge, Alaska. | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Charadriiformes |
| Family: | Laridae |
| Genus: | Larus |
| Species: | L. canus |
| Binomial name | |
|
Larus canus Linnaeus, 1758 |
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The common gull (Larus canus) is a medium-sized gull which breeds in northern Asia, northern Europe and northwestern North America. The North American subspecies is commonly referred to as the mew gull, although that name is also used by some authorities for the whole species. It migrates further south in winter. There are differing accounts as to how the species acquired its vernacular name (see Etymology section below).
Adult common gulls are 40–46 cm (16–18 in) long, noticeably smaller than the herring gull and slightly smaller than the ring-billed gull. It is further distinguished from the ring-billed gull by its shorter, more tapered bill, which is a more greenish shade of yellow and is 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, which is 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.
There are four subspecies, two of which are considered distinct species by some authorities:
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 2 to 320 or even 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. By contrast, the Alaskan population is only about 10,000 pairs.
The common gull occurs as a scarce winter visitor to coastal eastern Canada and as a vagrant to the northeastern USA. There is one recent record of a mew gull in Europe, on the Azores in 2003.
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Wikipedia