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The great black-backed gull (''Larus marinus'') is the largest member of the
gull Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century ...
family. Described by the
Cornell Lab of Ornithology The Cornell Lab of Ornithology is a member-supported unit of Cornell University in Ithaca, New York, which studies birds and other wildlife. It is housed in the Imogene Powers Johnson Center for Birds and Biodiversity in Sapsucker Woods Sanctuar ...
as "the king of the Atlantic waterfront", it is a very aggressive hunter, pirate, and scavenger. It breeds on the European and North American coasts and islands of the
North Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe a ...
and is fairly sedentary, though some move farther south or inland to large lakes or reservoirs. The adult great black-backed gull has a white head, neck and underparts, dark grey wings and back, pink legs and yellow bill.


Taxonomy

The great black-backed gull was one of the many species originally described by
Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, ...
in his 1758 10th edition of ''Systema Naturae'', and it still bears its original name of ''Larus marinus''. The scientific name is from
Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...
. ''Larus'' appears to have referred to a
gull Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century ...
or other large seabird. The specific name ''marinus'' means "marine", or when taken together, "sea gull". This predates Linnean taxonomy, as it had been called ''Larus ingens marinus'' by
Carolus Clusius Charles de l'Écluse, L'Escluse, or Carolus Clusius (19 February 1526 – 4 April 1609), seigneur de Watènes, was an Artois doctor and pioneering botanist, perhaps the most influential of all 16th-century scientific horticulturists. Life Clu ...
. The terms ''swaabie'' (from nrn, swartbak, lit=black back), ''baagie'' and ''baigie'' (, from ) are local names from the Shetland Islands.
Francis Willughby Francis Willughby (sometimes spelt Willoughby, la, Franciscus Willughbeius) FRS (22 November 1635 – 3 July 1672) was an English ornithologist and ichthyologist, and an early student of linguistics and games. He was born and raised at ...
called it the ''great black and white gull'' in the 17th century, noting that it was called the ''swarth-back'' in the
Faroe Islands The Faroe Islands ( ), or simply the Faroes ( fo, Føroyar ; da, Færøerne ), are a North Atlantic island group and an autonomous territory of the Kingdom of Denmark. They are located north-northwest of Scotland, and about halfway bet ...
.


Description

This is the largest gull in the world, considerably larger than a
herring gull Herring gull is a common name for several birds in the genus ''Larus'', all formerly treated as a single species. Three species are still combined in some taxonomies: * American herring gull (''Larus smithsonianus'') - North America * European h ...
(''Larus argentatus''). Only a few other gulls, including Pallas's gull (''Ichthyaetus ichthyaetus'') and
glaucous gull The glaucous gull (''Larus hyperboreus'') is a large gull, the second-largest gull in the world. It breeds in Arctic regions of the Northern Hemisphere and winters south to shores of the Holarctic. The genus name is from Latin ''larus'', which a ...
(''Larus hyperboreus''), come close to matching this species' size. It is long with a wingspan and a body weight of . In a sample of 2009 adults from the
North Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe a ...
, males were found to average and females were found to average . Some adult gulls with access to fisheries in the
North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian ...
can weigh up to roughly and averaged . An exceptionally large glaucous gull was found to outweigh any known great black-backed gull, although usually that species is slightly smaller. The great black-backed gull is bulky and imposing in appearance with a large, powerful bill. The standard measurements are: the
bill Bill(s) may refer to: Common meanings * Banknote, paper cash (especially in the United States) * Bill (law), a proposed law put before a legislature * Invoice, commercial document issued by a seller to a buyer * Bill, a bird or animal's beak Pla ...
is , the wing chord is and the tarsus is . The adult great black-backed gull is fairly distinctive, as no other very large gull with blackish coloration on its upper-wings generally occurs in the
North Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe a ...
. In other white-headed North Atlantic gulls, the mantle is generally a lighter gray color and, in some species, it is a light powdery color or even pinkish. It is grayish-black on the wings and back, with conspicuous, contrasting white "mirrors" at the wing tips. The legs are pinkish, and the bill is yellow or yellow-pink with some orange or red near tip of lower bill. The adult
lesser black-backed gull The lesser black-backed gull (''Larus fuscus'') is a large gull that breeds on the Atlantic coasts of Europe. It is migratory, wintering from the British Isles south to West Africa. It has increased dramatically in North America, most common alo ...
(''L. fuscus'') is distinctly smaller, typically weighing about half as much as a great black-back. The lesser black-back has yellowish legs and a mantle that can range from slate-gray to brownish-colored but it is never as dark as the larger species. A few superficially similar dark-backed, fairly large gulls occur in the Pacific Ocean or in the tropics, all generally far outside this species' range, such as the slaty-backed (''L. schistisagus''), the
western Western may refer to: Places *Western, Nebraska, a village in the US *Western, New York, a town in the US *Western Creek, Tasmania, a locality in Australia *Western Junction, Tasmania, a locality in Australia *Western world, countries that id ...
(''L. occidentalis'') and the
kelp gull The kelp gull (''Larus dominicanus''), also known as the Dominican gull, is a gull that breeds on coasts and islands through much of the Southern Hemisphere. The nominate ''L. d. dominicanus'' is the subspecies found around South America, part ...
(''L. dominicanus''). Juvenile birds of under a year old have scaly, checkered black-brown upper parts, the head and underparts streaked with gray brown, and a neat wing pattern. The face and nape are paler and the wing flight feathers are blackish-brown. The juvenile's tail is white with zigzag bars and spots at base and a broken blackish band near the tip. The bill of the juvenile is brownish-black with white tip and the legs dark bluish-gray with some pink tones. As the young gull ages, the gray-brown coloration gradually fades to more contrasting plumage and the bill darkens to black before growing paler. By the third year, the young gulls resemble a streakier, dirtier-looking version of the adult. They take at least four years to reach maturity, development in this species being somewhat slower than that of other large gulls. The call is a deep "laughing" cry, ''kaa-ga-ga'', with the first note sometimes drawn out in an almost
bovid The Bovidae comprise the biological family of cloven-hoofed, ruminant mammals that includes cattle, bison, buffalo, antelopes, and caprines. A member of this family is called a bovid. With 143 extant species and 300 known extinct species, t ...
-like sound. The voice is distinctly deeper than most other gull species. File:Great black-backed gull Larus marinus first-winter.jpg, First winter File:Great black-backed gull Larus marinus second-winter.jpg, Second winter File:Great black-backed gull Larus marinus third-winter.jpg, Third winter File:Great black-backed gull Larus marinus fourth-winter.jpg, Fourth winter


Distribution and habitat

This species can be found breeding in coastal areas from the extreme northwest portion of
Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-ei ...
, through much of coastal
Scandinavia Scandinavia; Sámi languages: /. ( ) is a subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, Norway, and S ...
, on the
Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain. The sea stretches from 53°N to 66°N latitude and from ...
coasts, to the coasts of northwestern
France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
, the
United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and ...
and
Ireland Ireland ( ; ga, Éire ; Ulster-Scots: ) is an island in the North Atlantic Ocean, in north-western Europe. It is separated from Great Britain to its east by the North Channel, the Irish Sea, and St George's Channel. Ireland is the s ...
. Across the northern portion of the Atlantic, this gull is distributed in
Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its ...
, the
Faroe Islands The Faroe Islands ( ), or simply the Faroes ( fo, Føroyar ; da, Færøerne ), are a North Atlantic island group and an autonomous territory of the Kingdom of Denmark. They are located north-northwest of Scotland, and about halfway bet ...
, southern
Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland ...
and on the Atlantic coasts of
Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by to ...
and the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...
. Though formerly mainly just a non-breeding visitor south of Canada in North America, the species has spread to include several colonies in the
New England New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York to the west and by the Canadian provinces ...
states and now breeds as far south as
North Carolina North Carolina () is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. The state is the List of U.S. states and territories by area, 28th largest and List of states and territories of the United ...
. Individuals breeding in harsher environments will migrate south, wintering on northern coasts of Europe from the Baltic Sea to southern
Portugal Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of th ...
, and regularly down to coastal
Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and ...
in North America. During the winter in the Baltic Sea, the bird usually stays close to the ice boundary. North of the
Åland Åland ( fi, Ahvenanmaa: ; ; ) is an autonomous and demilitarised region of Finland since 1920 by a decision of the League of Nations. It is the smallest region of Finland by area and population, with a size of 1,580 km2, and a populat ...
islands, the sea often freezes all the way from
Sweden Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic countries, Nordic c ...
to
Finland Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of Bot ...
, and then the bird migrates to open waters. Exceptionally, the species can range as far south as the
Caribbean The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean ...
and off the coast of northern South America. The great black-backed gull is found in a variety of coastal habitats, including rocky and sandy
coast The coast, also known as the coastline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. The Earth has around of coastline. Coasts are important zones in n ...
s and
estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environme ...
, as well as inland wetland habitats, such as
lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...
s,
pond A pond is an area filled with water, either natural or artificial, that is smaller than a lake. Defining them to be less than in area, less than deep, and with less than 30% emergent vegetation helps in distinguishing their ecology from tha ...
s,
river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of ...
s, wet fields and
moorland Moorland or moor is a type of habitat found in upland areas in temperate grasslands, savannas, and shrublands and montane grasslands and shrublands biomes, characterised by low-growing vegetation on acidic soils. Moorland, nowadays, generall ...
. They are generally found within striking distance of large bodies of water while ranging inland. Today, it is a common fixture at refuse dumps both along coasts and relatively far inland. The species also makes extensive use of dredge spoils, which, in the state of
New Jersey New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delawa ...
, are their most prevalent nesting sites. It generally breeds in areas free of or largely inaccessible to terrestrial predators, such as vegetated islands, sand
dune A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, f ...
s, flat-topped stacks, building
roof A roof ( : roofs or rooves) is the top covering of a building, including all materials and constructions necessary to support it on the walls of the building or on uprights, providing protection against rain, snow, sunlight, extremes of t ...
s and sometimes amongst bushes on
salt marsh A salt marsh or saltmarsh, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. It is domin ...
islands. During the winter, the great black-backed gull often travels far out to sea to feed.


Diet

Great black-backed gulls are opportunistic feeders,
apex predator An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic lev ...
s, and are very curious. They will investigate any small organism they encounter and will readily eat almost anything that they can swallow. They get much of their dietary energy from scavenging, with
refuse Waste (or wastes) are unwanted or unusable materials. Waste is any substance discarded after primary use, or is worthless, defective and of no use. A by-product, by contrast is a joint product of relatively minor economic value. A waste prod ...
, most provided directly by humans, locally constituting more than half of their diet. The proliferation of garbage or refuse dumps has become a major attractant to this and all other non-specialized gull species in its range. A study to investigate how much time they spend foraging at refuse dumps in
Massachusetts Massachusetts (Massachusett: ''Muhsachuweesut Massachusett_writing_systems.html" ;"title="nowiki/> məhswatʃəwiːsət.html" ;"title="Massachusett writing systems">məhswatʃəwiːsət">Massachusett writing systems">məhswatʃəwiːsət'' En ...
found great black-backed gulls were only observed actively foraging 19% of their time there, eating less garbage than other common gulls, and spent most of their time roosting or loafing. Like most gulls, Great Black-backed Gulls regularly capture fish and any fish smaller than itself found close to the surface of the water are potential prey. Stomach contents of great black-backed gulls usually show fish to be the primary food. On
Sable Island Sable Island (french: île de Sable, literally "island of sand") is a small Canadian island situated southeast of Halifax, Nova Scotia, and about southeast of the closest point of mainland Nova Scotia in the North Atlantic Ocean. The island ...
in
Nova Scotia Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland". Most of the population are native Eng ...
, 25% of the stomach contents consisted of fish, but 96% of the regurgitations given to young consisted of fish. Similarly, on
Great Island Great Island () is an island in Cork Harbour, at the mouth of the River Lee and close to the city of Cork, Ireland. The largest town on the island is Cobh (called Queenstown from 1849 to 1922). The island's economic and social history has histo ...
in
Newfoundland Newfoundland and Labrador (; french: Terre-Neuve-et-Labrador; frequently abbreviated as NL) is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region ...
, 25% of the stomach contents were fish but 68% of regurgitants were fish. The most regularly reported fish eaten in
Nova Scotia Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland". Most of the population are native Eng ...
and
Newfoundland Newfoundland and Labrador (; french: Terre-Neuve-et-Labrador; frequently abbreviated as NL) is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region ...
were capelin (''Mallotus villosus''), Atlantic cod (''Gadus morhua''), Atlantic tomcod (''Microgadus tomcod''), Atlantic mackerel (''Scomber scombrus''),
Atlantic herring Atlantic herring (''Clupea harengus'') is a herring in the family Clupeidae. It is one of the most abundant fish species in the world. Atlantic herrings can be found on both sides of the Atlantic Ocean, congregating in large schools. They can ...
(''Clupea harengus'') and sand lance (''Ammodytes hexapterus''). Other prey often includes various
squid True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fittin ...
,
Jonah crab The Jonah crab (''Cancer borealis'') is a marine brachyuran crab that inhabits waters along the east coast of North America from Newfoundland to Florida. Jonah crabs possess a rounded, rough-edged carapace with small light spots, and robust claws ...
s (''Cancer borealis''), rock crabs (''Cancer irroratus''),
sea urchin Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) o ...
s, green crabs (''Carcinus maenas''), starfish (''
Asterias forbesi ''Asterias forbesi'', commonly known as Forbes sea star, is a species of starfish in the family Asteriidae. It is found in shallow waters in the northwest Atlantic Ocean and the Caribbean Sea. Description left, Underside of ''Asterias forbesi'' ...
'' and ''
Asterias rubens The common starfish, common sea star or sugar starfish (''Asterias rubens'') is the most common and familiar starfish in the north-east Atlantic. Belonging to the family Asteriidae, it has five arms and usually grows to between 10–30  ...
'') and other
echinoderm An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the s ...
s,
crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...
s and mollusks when they come across the opportunity. From observations in northern
New England New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York to the west and by the Canadian provinces ...
, 23% of observed prey was echinoderms and 63% was
crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...
s. Unlike most other ''Larus'' gulls, they are highly predatory and frequently
hunt Hunting is the human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products (fur/ hide, bone/tusks, horn/antler, e ...
and kill any prey smaller than themselves, behaving more like a
raptor Raptor or RAPTOR may refer to: Animals The word "raptor" refers to several groups of bird-like dinosaurs which primarily capture and subdue/kill prey with their talons. * Raptor (bird) or bird of prey, a bird that primarily hunts and feeds on ...
than a typical larid gull. Lacking the razor-sharp
talons A claw is a curved, pointed appendage found at the end of a toe or finger in most amniotes (mammals, reptiles, birds). Some invertebrates such as beetles and spiders have somewhat similar fine, hooked structures at the end of the leg or tarsus ...
and curved, tearing beak of a raptor, the great black-backed gull relies on aggression, physical strength and endurance when hunting. When attacking other animals, they usually attack
seabird Seabirds (also known as marine birds) are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same enviro ...
eggs, nestlings or fledglings at the nest, perhaps most numerously
tern Terns are seabirds in the family Laridae that have a worldwide distribution and are normally found near the sea, rivers, or wetlands. Terns are treated as a subgroup of the family Laridae which includes gulls and skimmers and consists of e ...
s, but also including smaller gull species as well as
eider Eiders () are large seaducks in the genus ''Somateria''. The three extant species all breed in the cooler latitudes of the Northern Hemisphere. The down feathers of eider ducks, and some other ducks and geese, are used to fill pillows and quil ...
s,
gannet Gannets are seabirds comprising the genus ''Morus'' in the family Sulidae, closely related to boobies. Gannets are large white birds with yellowish heads; black-tipped wings; and long bills. Northern gannets are the largest seabirds in the ...
s and various
alcids An auk or alcid is a bird of the family Alcidae in the order Charadriiformes. The alcid family includes the murres, guillemots, auklets, puffins, and murrelets. The word "auk" is derived from Icelandic ''álka'', from Old Norse ''alka'' (a ...
. In
Newfoundland Newfoundland and Labrador (; french: Terre-Neuve-et-Labrador; frequently abbreviated as NL) is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region ...
and
Nova Scotia Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland". Most of the population are native Eng ...
, 10% of the stomach contents of great black-backed gulls was made up of birds, while a further 17% of stomach contents was made up of
tern Terns are seabirds in the family Laridae that have a worldwide distribution and are normally found near the sea, rivers, or wetlands. Terns are treated as a subgroup of the family Laridae which includes gulls and skimmers and consists of e ...
eggs alone. Adult or fledged juveniles of various bird species have also been predaceously attacked. Some fully-fledged or adult birds observed to be hunted in flight or on the ground by great black-backed gulls have included ''
Anas ''Anas'' is a genus of dabbling ducks. It includes the pintails, most teals, and the mallard and its close relatives. It formerly included additional species but following the publication of a molecular phylogenetic study in 2009 the genus was s ...
'' ducks,
ruddy duck The ruddy duck (''Oxyura jamaicensis'') is a duck from North America and one of the stiff-tailed ducks. The genus name is derived from Ancient Greek ''oxus'', "sharp", and ''oura'', "tail", and ''jamaicensis'' is "from Jamaica". Taxonomy The r ...
s (''Oxyura jamaicensis''), buffleheads (''Bucephala albeola''), Manx shearwaters (''Puffinus puffinus''),
pied-billed grebe The pied-billed grebe (''Podilymbus podiceps'') is a species of the grebe family of water birds. Because the Atitlán grebe (''Podilymbus gigas'') has become extinct, the Pied-Billed Grebe is now the sole extant member of the genus ''Podilymbus'' ...
s (''Podilymbus podiceps''),
common moorhen The common moorhen (''Gallinula chloropus''), also known as the waterhen or swamp chicken, is a bird species in the rail (bird), rail family (Rallidae). It is distributed across many parts of the Old World. The common moorhen lives around well-v ...
s (''Gallinula chloropus''),
tern Terns are seabirds in the family Laridae that have a worldwide distribution and are normally found near the sea, rivers, or wetlands. Terns are treated as a subgroup of the family Laridae which includes gulls and skimmers and consists of e ...
s, Atlantic puffins (''Fratercula arctica''),
Dovekie The little auk or dovekie (''Alle alle'') is a small auk, the only member of the genus ''Alle''. ''Alle'' is the Sami name of the long-tailed duck; it is onomatopoeic and imitates the call of the drake duck. Linnaeus was not particularly fam ...
(''Alle alle''),
coot Coots are medium-sized water birds that are members of the rail family, Rallidae. They constitute the genus ''Fulica'', the name being the Latin term for "coot". Coots have predominantly black plumage, and—unlike many rails—they are usually ...
s (''Fulica'' ssp.),
glossy ibis The glossy ibis (''Plegadis falcinellus'') is a water bird in the order Pelecaniformes and the ibis and spoonbill family Threskiornithidae. The scientific name derives from Ancient Greek ''plegados'' and Latin, ''falcis'', both meaning "sickle" a ...
es (''Plegadis falcinellus''),
rock pigeon The rock dove, rock pigeon, or common pigeon ( also ; ''Columba livia'') is a member of the bird family Columbidae (doves and pigeons). In common usage, it is often simply referred to as the "pigeon". The domestic pigeon (''Columba livia domes ...
s (''Columba livia'') and even predatory birds such as
hen harrier The hen harrier (''Circus cyaneus'') is a bird of prey. It breeds in Eurasia. The term "hen harrier" refers to its former habit of preying on free-ranging fowl. It migrates to more southerly areas in winter. Eurasian birds move to southern Eur ...
s (''Circus cyaneus''). When attacking other flying birds, the great black-backed gulls often pursue them on the wing and attack them by jabbing with their bill, hoping to bring down the other bird either by creating an open wound or simply via exhaustion. They may kill healthy adult birds weighing up to at least but take exclusively the small young of larger birds such as
common eider The common eider (pronounced ) (''Somateria mollissima''), also called St. Cuthbert's duck or Cuddy's duck, is a large ( in body length) sea-duck that is distributed over the northern coasts of Europe, North America and eastern Siberia. It breed ...
(''Somateria mollissima'') and cormorants. They will also catch flying
passerine A passerine () is any bird of the order Passeriformes (; from Latin 'sparrow' and '-shaped'), which includes more than half of all bird species. Sometimes known as perching birds, passerines are distinguished from other orders of birds by th ...
s, which they typically target while the small birds are exhausted from migration and swallow them immediately. Great black-backed gull also feed on land animals, including rats (''Rattus'' ssp.) at garbage dumps, rabbits (''Oryctolagus cuniculus'') and even sickly lambs (''Ovis aries''). Most foods are swallowed whole, including most fish and even other gulls. When foods are too large to be swallowed at once, they will sometimes be shaken in the bill until they fall apart into pieces. Like some other gulls, when capturing molluscs or other hard-surfaced foods such as
egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...
s, they will fly into the air with it and drop it on rocks or hard earth to crack it open. Alternate foods, including
berries A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone or pit, although many pips or seeds may be present. Common examples are strawberries, rasp ...
and
insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...
s, are eaten when available. They will readily exploit easy food sources, including chum lines made by boats at sea. They are skilled kleptoparasites who will readily pirate fish and other prey captured by other birds and dominate over other gulls when they encounter them. At tern colonies in coastal
Maine Maine () is a state in the New England and Northeastern regions of the United States. It borders New Hampshire to the west, the Gulf of Maine to the southeast, and the Canadian provinces of New Brunswick and Quebec to the northeast and ...
,
American herring gull The American herring gull or Smithsonian gull (''Larus smithsonianus'' or ''Larus argentatus smithsonianus'') is a large gull that breeds in North America, where it is treated by the American Ornithological Society as a subspecies of herring gul ...
s (''L. smithsonianus'') occasionally also attack nestling and fledgling terns but in a great majority of cases were immediately pirated of their catch by great black-backs. In one observation, an adult great black-back was seen to rob a female peregrine falcon (''Falco peregrinus'') of a freshly caught gadwall (''Anas strepera''). In another case, a third-year great black-back was observed fighting an adult female northern goshawk (''Accipiter gentilis'') off its kill, although the goshawk attempted to strike the gull before leaving. Due to their method of using intimidation while encountering other water and raptorial birds, the species has been referred to as a "merciless tyrant". Naturally, these gulls are attracted to the surface activity of large marine animals, from
Atlantic bluefin tuna The Atlantic bluefin tuna (''Thunnus thynnus'') is a species of tuna in the family Scombridae. It is variously known as the northern bluefin tuna (mainly when including Pacific bluefin as a subspecies), giant bluefin tuna or individuals excee ...
(''Thunnus thynnus'') to
humpback whale The humpback whale (''Megaptera novaeangliae'') is a species of baleen whale. It is a rorqual (a member of the family Balaenopteridae) and is the only species in the genus ''Megaptera''. Adults range in length from and weigh up to . The hu ...
s (''Megaptera novaeangliae''), to capture fish driven to the surface by such creatures.


Breeding

This species breeds singly or in small colonies, sometimes in the middle of a ''Larus argentatus'' colony. Young adult pair formation occurs in March or April. The following spring the same birds usually form a pair again, meeting at the previous year's nest. If one of the birds doesn't appear, the other bird begins looking for a new mate. Usually a single bird does not breed in that season. They make a lined nest on the ground often on top of a rocky stack, fallen log or other obstructing object which can protect the eggs from the elements. Usually, several nest scrapes are made before the one deemed best by the parents is selected and then lined with grass, seaweed or moss or objects such as rope or plastic. When nesting on roofs in urban environments, previous year's nests are often reused over and over again. The female lays usually three eggs sometime between late April and late June. When only two eggs are found in a nest, the reason is almost always that one egg, for one reason or another, has been destroyed. It takes around one week for the female to produce the three eggs, and the incubation doesn't begin until all three eggs are laid. Hence all three chicks are hatched the same day. The birds are usually successful in bringing up all the three chicks. The eggs are greenish-brown with dark speckles and blotches. Both parents participate in the incubation stage, which lasts for approximately 28 days. During this time, the birds attempt to avoid being noticed and stay silent. The breeding pair are devoted parents who both take shifts brooding the young, defending the nest and gathering food. Young great black-backed gulls leave the nest area at 50 days of age and may remain with their parents for an overall period of around six months, though most fledglings choose to congregate with other immature gulls in the search for food by fall. These gulls reach breeding maturity when they obtain adult plumage at four years, though may not successfully breed until they are six years old.


Longevity and mortality

This is a relatively long-living bird. The maximum recorded age for a wild great black-backed gull is 27.1 years. This species is rarely kept in captivity, but domestically kept
European herring gull The European herring gull (''Larus argentatus'') is a large gull, up to long. One of the best-known of all gulls along the shores of Western Europe, it was once abundant. It breeds across Northern Europe, Western Europe, Central Europe, Eastern ...
s have been known to live for over 44 years and generally larger birds can outlive smaller ones. Mortality typically occurs in the early stages of life, when harsh weather conditions (including flooding) and starvation can threaten them, as well as predators. Chicks and eggs are preyed on by
crow A crow is a bird of the genus '' Corvus'', or more broadly a synonym for all of ''Corvus''. Crows are generally black in colour. The word "crow" is used as part of the common name of many species. The related term "raven" is not pinned scientifica ...
s (''Corvus'' ssp.),
cat The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...
s (''Felis catus''), other
gull Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century ...
s,
raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the common raccoon to distinguish it from other species, is a mammal native to North America. It is the largest of the procyonid family, having a body length of , and a body weight of ...
s (''Procyon lotor'') and rats (''Rattus'' ssp.). The bald eagle (''Haliaeetus leucocephalus''),
white-tailed eagle The white-tailed eagle (''Haliaeetus albicilla'') is a very large species of sea eagle widely distributed across temperate Eurasia. Like all eagles, it is a member of the family Accipitridae (or accipitrids) which includes other diurnal raptors ...
(''H. albicilla'') and
golden eagle The golden eagle (''Aquila chrysaetos'') is a bird of prey living in the Northern Hemisphere. It is the most widely distributed species of eagle. Like all eagles, it belongs to the family Accipitridae. They are one of the best-known birds of ...
(''Aquila chrysaetos'') are the only birds known to habitually predate healthy, fully grown great black-backed gulls. In one study from
Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and the ...
, great black-backed gulls were the fifth highest frequency prey item for white-tailed eagles and gulls are prone to
mobbing Mobbing, as a sociological term, means bullying of an individual by a group, in any context, such as a family, peer group, school, workplace, neighborhood, community, or online. When it occurs as physical and emotional abuse in the workplace, suc ...
these huge eagles. The great black-backed gull has also been observed engaging in aerial combat with bald eagles, attacking the eagles and chasing them away. A great skua (''Stercorarius skua'') was filmed in Scotland unsuccessfully attempting to kill a second or third year great black-backed gull. In
Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and the ...
, great black-backed gulls have also been reported to fall prey to
Eurasian eagle-owl The Eurasian eagle-owl (''Bubo bubo'') is a species of eagle-owl that resides in much of Eurasia. It is also called the Uhu and it is occasionally abbreviated to just the eagle-owl in Europe. It is one of the largest species of owl, and femal ...
s (''Bubo bubo'').
Killer whale The orca or killer whale (''Orcinus orca'') is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only extant species in the genus ''Orcinus'' and is recognizable by its black-and-white ...
s (''Orcinus orca'') and sharks also reportedly prey upon adult and juvenile birds at sea. In some biomes, where large eagles are absent the great black-backed gull may be considered the
apex predator An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic lev ...
.


Status

Historically, the great black-backed gull was harvested for its feathers, which were used in the hat-making trade, and this species was extirpated from large parts of its range as a result of this exploitation. Today, however, its adaptability to human presence and the use of urban environments as artificial nesting sites has resulted in the great black-backed gull rapidly increasing in number and range. It is now a widespread and abundant species in its range and its numbers have increased to such high levels in some areas that it is often seen as a pest species, especially near airports where it risks collisions with airplanes, and in some coastal areas where it sometimes outcompetes or hunts rarer seabirds, such as Atlantic puffins, possibly resulting in conservationist intervention. The increase and expansion of great black-backed gulls has been attributed to increasing winter fishery activities in the
North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian ...
. Although there are no known major threats to the great black-backed gull, high levels of toxic pollutants, which are ingested with contaminated prey, are often found in individuals and eggs, reducing reproductive success. Breeding is also interrupted by human disturbance, which can lead to eggs being abandoned, leaving them vulnerable to exposure and predation.


Gallery

File:Larus marinus head 01.jpg, Great black-backed gull has a bulky, powerful beak File:LarusMarinus and LarusArgentatus.JPG, ''Larus marinus'' and ''Larus argentatus'' together, Øresund File:Svartbak.jpg File:Larus marinus EM1B0978 (34665035760).jpg File:Larus marinus 2.jpg, Great black-backed gulls displaying File:Great Black-backed Gull Juvenile.jpg, Juvenile, Cape May Point, New Jersey File:Larus argentatus, immature, Trassenheide, Deutschland.jpg, Juvenile, Trassenheide, Germany File:Larus marinus eggs.jpg, Great black-backed gull nest and eggs File:Larus marinus nestlings.jpg, Chicks File:Great Black-backed Gull flock.jpg, Flock taking off during southern migration through Ottawa, Ontario File:Greater Black-backed Gull from the Crossley ID Guide Britain and Ireland.jpg, ID composite File:Great Blacked Backed Gull (19244633653).jpg File:Great black-backed gull (Larus marinus) in flight.jpg Larus marinus MHNT.ZOO.2010.11.127.9.jpg, ''Larus marinus'' - MHNT


References


Further reading

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External links

* * * * * * * {{Taxonbar , from=Q26629 Larus, great black-backed gull Native birds of Eastern Canada Birds of Europe Birds of Iceland Birds of Scandinavia Birds described in 1758, great black-backed gull Taxa named by Carl Linnaeus, great black-backed gull Articles containing video clips