American Herring Gull
Encyclopedia
The American Herring Gull or Smithsonian Gull (Larus smithsonianus) is a large gull
Gull
Gulls are birds in the family Laridae. They are most closely related to the terns and only distantly related to auks, skimmers, and more distantly to the waders...

 which breeds in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

. It is often treated as a subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 of the European Herring Gull (L. argentatus) but is now regarded as a separate species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 by some authorities.

Adults are white with gray back and wings, black wingtips with white spots, and pink legs. Immature birds are gray-brown and are darker and more uniform than European Herring Gulls with a dark tail.

It occurs in a variety of habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...

s including coasts, lakes, rivers and garbage dumps. Its broad diet includes invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...

s, fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 and many other items. It usually nests
Bird nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American Robin or Eurasian Blackbird, or the elaborately woven hanging nest of the...

 near water, laying around three eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...

 in a scrape on the ground.

Taxonomy

It was first described as a new species in 1862 by Elliott Coues
Elliott Coues
Elliott Coues was an American army surgeon, historian, ornithologist and author.Coues was born in Portsmouth, New Hampshire. He graduated at Columbian University, Washington, D.C., in 1861, and at the Medical school of that institution in 1863...

 based on a series of specimens from the Smithsonian Institution
Smithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...

. It was later reclassified as a subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 of the Herring Gull (Larus argentatus). The taxonomy of the Herring Gull group is very complicated and much is still controversial and uncertain. A 2002 study suggested that the American Herring Gull is not closely related to European Herring Gulls, belonging instead to a separate clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 of gulls. Several authorities such as the Association of European Rarities Committees
Association of European Rarities Committees
The Association of European Rarities Committees is a co-ordinating and liaison body for the bird rarities committees of Europe and other nearby countries.It was created in 1993 at a meeting of European rarities committees on the German island of Heligoland....

 and British Ornithologists' Union
British Ornithologists' Union
The British Ornithologists' Union aims to encourage the study of birds in Britain, Europe and elsewhere, in order to understand their biology and to aid their conservation....

 now recognize it as a separate species. The BOU also includes the East Siberian Gull
East Siberian Gull
The Vega Gull or East Siberian Gull, Larus vegae, is a large gull of the Herring Gull/Lesser Black-backed Gull complex which breeds in North-east Asia. Its classification is still controversial and uncertain. It is variously treated as a separate species, as a subspecies of American Herring Gull...

 (Larus vegae) of north-east Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

 within the American Herring Gull. The American Ornithologists' Union
American Ornithologists' Union
The American Ornithologists' Union is an ornithological organization in the USA. Unlike the National Audubon Society, its members are primarily professional ornithologists rather than amateur birders...

 has not adopted the split and continues to treat the American Herring Gull as a subspecies of Larus argentatus.

Description

It is a large gull with a long powerful bill, full chest and sloping forehead. Males are 60–66 cm long and weigh 1050–1250 grams. Females are 56–62 cm long and weigh 800–980 grams. The wingspan is 120–150 cm.

Breeding adults have a white head, rump, tail and underparts and a pale gray back and upperwings. The wingtips are black with white spots known as "mirrors" and the rear edge of the wing is white. The underwing is grayish with dark tips to the outer primary feathers. The legs and feet are normally pink but can have a bluish tinge, or occasionally be yellow. The bill is yellow with a red spot on the lower mandible. The eye is bright, pale to medium yellow, with a bare yellow or orange ring around it. In winter, the head and neck are streaked with brown.

Young birds take four years to reach fully adult plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...

. During this time they go through several plumage stages and can be very variable in appearance. First-winter birds are gray-brown with a dark tail, a brown rump with dark bars, dark outer primaries and pale inner primaries, dark eyes and a dark bill which usually develops a paler base through the winter. The head is often paler than the body. Second-winter birds typically have a pale eye, pale bill with black tip, pale head and begin to show gray feathers on the back. Third-winter birds are closer to adults but still have some black on the bill and brown on the body and wings and have a black band on the tail.

Voice

It has no song but has a variety of cries and calls. The "long call" is a series of notes during which the head is dipped then raised. The "choking call" is produced during courtship displays or territorial disputes. Juvenile birds emit high-pitched plaintive cries to elicit feeding behavior from a parent, and may also emit a clicking distress call when a parent suddenly flies off.

Similar species

Adult European Herring Gulls are very similar to American Herring Gulls but those of the subspecies L. a. argenteus are smaller than many American birds while those of the northern subspecies L. a. argentatus are typically darker gray above. European birds lack the long gray tongues on the 6th, 7th and 8th primaries and solid black markings on the 5th and 6th primaries that are shown by American Herring Gulls. First-winter European birds have more checkered upperparts, more streaked underparts, and a paler rump and base to the tail.

Distribution and habitat

The breeding range extends across the northern part of North America from central and southern Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

 to the Great Lakes
Great Lakes
The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...

 and north-east coast of the USA south to North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...

. It breeds over most of Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

 apart from the southwest and Arctic regions.

Birds are present all year in southern Alaska, the Great Lakes and north-east USA but most birds winter to the south of the breeding range as far as Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

 with small numbers reaching Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...

, Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...

 and the West Indies. Vagrants have reached Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...

 and Venezuela
Venezuela
Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...

 and there is a report from Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...

 and another from Peru
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....

. The first European record was of a bird ringed in New Brunswick
New Brunswick
New Brunswick is one of Canada's three Maritime provinces and is the only province in the federation that is constitutionally bilingual . The provincial capital is Fredericton and Saint John is the most populous city. Greater Moncton is the largest Census Metropolitan Area...

 which was caught on a boat in Spanish
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

 waters in 1937 and there are have a number of additional records from Western Europe since 1990. The first British record was in 1994 in Cheshire.

It usually nests in colonies near water on coasts, islands and cliffs. It also nests on rooftops in some cities. It feeds at sea and on beaches, mudflats, lakes, rivers, fields and refuse dumps. It roosts in open areas close to feeding sites.

Behavior

Feeding

It has a varied diet including marine invertebrates such as mussel
Mussel
The common name mussel is used for members of several families of clams or bivalvia mollusca, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval.The...

s, crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...

s, sea urchin
Sea urchin
Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from across. Common colors include black and dull...

s and squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...

, fish such as capelin
Capelin
The capelin or caplin, Mallotus villosus, is a small forage fish of the smelt family found in the Atlantic and Arctic oceans. In summer, it grazes on dense swarms of plankton at the edge of the ice shelf. Larger capelin also eat a great deal of krill and other crustaceans...

, alewife
Alewife
The alewife is a species of herring. There are anadromous and landlocked forms. The landlocked form is also called a sawbelly or mooneye...

 and smelt, insects and other birds including their chicks and eggs. It often feeds on carrion
Carrion
Carrion refers to the carcass of a dead animal. Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters include vultures, hawks, eagles, hyenas, Virginia Opossum, Tasmanian Devils, coyotes, Komodo dragons, and burying beetles...

 and human refuse. Food is plucked from the surface of the shore or sea or is caught by dipping underwater or by shallow plunge-diving.

Reproduction

Pairs form in March or April. The nest is a scrape on the ground lined with vegetation such as grass and seaweed and with feathers. Usually three eggs are laid over a four to six day period. They are 72 mm long and are variable in color with brown markings on a pale blue, olive or cinnamon background. The eggs are incubated
Avian incubation
Incubation refers to the process by which certain oviparous animals hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period. Especially in domestic fowl, the act of...

 for 30–32 days beginning when the second egg is laid. The young birds fledge
Fledge
Fledge is the stage in a young bird's life when the feathers and wing muscles are sufficiently developed for flight. It also describes the act of a chick's parents raising it to a fully grown state...

 after 6–7 weeks and are fed in the nest area for several more weeks. They continue to be cared for by the parents until they are about 6 months old. Both parents are involved in building the nest, incubating the eggs and feeding the young.
It has been observed that some pairs cement a close bond, staying in watchful proximity of each other year round; Other gulls display more independence, but may take the same mate each spring.

Status

The species became quite rare during the 19th century when it was hunted for its eggs and feathers. From the 1930s to 1960s, it increased rapidly due to protection from hunting, increased waste from fisheries to feed on and less competition for small fish and invertebrates as humans reduced the populations of large fish, whale
Whale
Whale is the common name for various marine mammals of the order Cetacea. The term whale sometimes refers to all cetaceans, but more often it excludes dolphins and porpoises, which belong to suborder Odontoceti . This suborder also includes the sperm whale, killer whale, pilot whale, and beluga...

s and pinniped
Pinniped
Pinnipeds or fin-footed mammals are a widely distributed and diverse group of semiaquatic marine mammals comprising the families Odobenidae , Otariidae , and Phocidae .-Overview: Pinnipeds are typically sleek-bodied and barrel-shaped...

s. Numbers leveled off during the 1970s and 80s and may now be declining in some areas.

Identification

  • Lonergan, Pat and Killian Mullarney
    Killian Mullarney
    Killian Mullarney is an Irish ornithologist, bird artist and bird tour leader. He designed a series of Irish definitive stamps for An Post illustrating Irish birds issued between 1997 and 2004....

     (2004) Identification of American Herring Gull in a western European context Dutch Birding
    Dutch Birding
    Dutch Birding is an ornithological magazine published by the Dutch Birding Association. Its editor is Arnoud van den Berg. It was first published in 1979....

    26(1): 1-35

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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