Herring Gull
2008/9 Schools Wikipedia Selection. Related subjects: Birds
| Herring Gull | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 Breeding-plumaged adult of the subspecies L. a. argenteus on Heligoland
|
||||||||||||||
| Conservation status | ||||||||||||||
 Least Concern ( IUCN 3.1) |
||||||||||||||
| Scientific classification | ||||||||||||||
|
||||||||||||||
| Binomial name | ||||||||||||||
| Larus argentatus Pontoppidan, 1763, Denmark |
The Herring Gull, Larus argentatus, is a large gull (up to 26 inches or 66 cm long) and "is the most abundant and best known of all gulls along the shores of Asia. western Europe, and North America." It breeds across North America, Europe and Asia. Some Herring Gulls, especially those resident in colder areas, migrate further south in winter, but many are permanent residents, e.g. those on the lower Great Lakes, on the east coast of North America or at the North Sea shores. Herring Gulls are also abundant around inland garbage dumps, and some have even adapted to life in inland cities.
Taxonomy
The taxonomy of the Herring Gull / Lesser Black-backed Gull complex is very complicated, different authorities recognising between two and eight species.
This group has a ring distribution around the northern hemisphere. Differences between adjacent forms in this ring are fairly small, but by the time the circuit is completed, the end members, Herring Gull and Lesser Black-backed Gull, are clearly different species.
The Association of European Rarities Committees recognises six species:
- Herring Gull, Larus argentatus
- American Herring Gull, Larus smithsonianus
- Caspian Gull, Larus cachinnans
- Yellow-legged Gull, Larus michahellis
- East Siberian Gull, Larus vegae
- Armenian Gull, Larus armenicus
Subspecies
- L. a. argentatus, the nominate form, breeds in Scandinavia and north-west Russia. Northern and eastern populations migrate south-west in winter. It is a large, bulky gull with extensive white in the wingtips.
- L. a. argenteus breeds in Western Europe in Iceland, the Faroes, Britain, Ireland, France, Belgium, the Netherlands and Germany. Many birds are resident while others make short-distance migratory journeys. It is smaller than L. a. argentatus with more black and less white in the wingtips and paler upperparts.
The two following taxa are classified as subspecies of Larus argentatus by some authorities such as the American Ornithologists' Union and Handbook of the Birds of the World. Others such as the Association of European Rarities Committees and British Ornithologists' Union now regard them as one or two separate species.
- L. (a.) smithsonianus, American Herring Gull, breeds in Alaska, Canada and the north-east United States. Many birds migrate southwards in winter, reaching as far as Central America and the West Indies. Immature birds tend to be darker and more uniformly brown than European Herring Gulls and have a dark tail.
- L. (a.) vegae, Vega Gull, breeds in north-east Siberia. It winters in Japan, Korea, eastern China and Taiwan.
Several other gulls have been included in this species in the past but are now normally considered separate, e.g. Yellow-legged Gull (L. michahellis), Caspian Gull (L. cachinnans), Armenian Gull (L. armenicus) and Heuglin's Gull (L. heuglini).
Description
The average Herring Gull is 55-66 cm (22-26 inches) long with a wingspan of 138-150 cm. Adults in breeding plumage have a grey back and upperwings and white head and underparts. The wingtips are black with white spots known as "mirrors" . The bill is yellow with a red spot and there is a ring of bare yellow skin around the pale eye. The legs are normally pink at all ages but can be yellowish, particularly in the Baltic population which was formerly regarded as a separate subspecies "L. a. omissus". Non-breeding adults have brown streaks on the head and neck. Male and female plumage is identical at all stages of development, however adult males are often larger.
Juvenile and first-winter birds are mainly brown with darker streaks and have a dark bill and eyes. Second-winter birds have a whiter head and underparts with less streaking and the back is grey. Third-winter individuals are similar to adults but retain some of the features of immature birds such as brown feathers in the wings and dark markings on the bill.
Similar species
Adult Herring Gulls are similar to Ring-billed Gulls but are much larger, have pinkish legs, and a much thicker yellow bill with more pronounced gonys. First-winter Herring Gulls are much browner, but second and third-winter birds can be confusing since soft part colors are variable and third-year Herring Gull often show a ring around the bill. Such birds are most easily distinguished by the larger size and larger bill of Herring Gull.
Voice
The loud laughing call is well-known in the northern hemisphere. The Herring Gull also has a yelping alarm call and a low barking anxiety call.
Behaviour
Herring Gull flocks have a loose pecking order, based on size, aggressiveness and physical strength. Communication between these birds is complex and highly-developed - employing both calls and body language. Two identical vocalizations can have very different (sometimes opposite) meanings, for example - depending on the positionings of the head, body, wings and tail relative to each other and the ground in the calling gull.
Unlike many flocking birds, Herring Gulls do not engage in social grooming and keep physical contact between individuals to a minimum. Outside of the male/female and parent/chick relationship, each Herring Gull attempts to maintain a respectful 'safe distance' from others of its kind. Any breach of this results in fighting, though severe injuries are seldom inflicted.
Herring Gulls are known to be capable of seeing ultraviolet light.
Parasites of Herring gulls include the fluke Microphallus piriformes.
Diet
These are omnivores like most Larus gulls, and will scavenge on rubbish tips and elsewhere, as well as seeking suitable small prey in fields or on the coast, or robbing plovers or lapwings of their catches. Despite their name, they have no special preference for herrings.
Reproduction
Two to four eggs, usually three, are laid on the ground or cliff ledges in colonies, and are defended vigorously by this large gull. The eggs are a dark blotched, olive colour. They are incubated for 28-30 days.
Juveniles use their beaks to "knock" on the red spot on the beaks of adults to indicate hunger. Parents typically disgorge food for their offspring when they are "knocked". The young birds are able to fly 35-40 days after hatching.