Gulls

views updated May 29 2018

Gulls

Gulls in North America

Gulls and people

Resources

Gulls are 51 species of seabirds, in the subfamily Larinae of the family Laridae, which also includes the terns. Gulls occur in a wide range of coastal habitats, ranging from inland lakes, rivers, and wetlands, to marine shores and estuaries. Their distribution is virtually worldwide, but most species occur in the Northern Hemisphere.

Species of gulls range in body length from 8-32 in (20-81 cm). Their wings are long and pointed, and gulls have a short squared tail. The legs are short and stout, and the feet have webbing between the toes, useful for swimming. The bill is rather stout and hooked at the end.

Gulls are typically white-colored, with the wings and back, known as the mantle, being colored gray or black. Some species have a black head during the breeding season. The sexes are alike in color and shape. Immature birds are usually much darker colored than the adults, but in a few species they are whiter.

Gulls are strong fliers, and they can undertake longdistance movements for feeding or during their migrations. Gulls often soar and glide effortlessly, whenever possible using the wind and updrafts to transport them where they want to go. Gulls are gregarious animals, both during the breeding season when they nest in loose colonies and during the non-breeding season when they often occur in large foraging and roosting flocks.

Gulls are highly omnivorous and opportunistic animals, eating a wide range of foods, depending on availability. However, they mostly feed on animal biomass, and less commonly on vegetation, especially fruits. Gulls are capable fishers, aerially spotting a fish as it swims near the surface and catching it in their beak. This is usually done either by picking the food off the surface of the water, or sometimes by catching the prey after a headlong, shallow plunge into the water. Gulls also predate on the young of other sea-birds when the opportunity presents itself. In addition, they scavenge carrion whenever it is available. Many species also scavenge the edible refuse of humans, near garbage dumps, fishing boats, fish-processing factories, and similar sorts of places.

Gulls nest in loosely structured colonies, generally building a moundlike nest out of grasses and seaweeds. Most species nest on the ground, but a few nest on cliff ledges. Gulls lay one to four greenish, speckled eggs. The eggs are incubated by both sexes of the pair, which also share the raising of the young. Depending on the species, gulls can take as long as four or five years to reach sexual maturity. Some species of gulls are long-lived, and leg-ringed individuals have reached ages greater than 40 years.

Gulls in North America

The name sea-gull does not really apply to any particular species of bird. However, this name would be most appropriately used to describe the herring gull (Larus argentatus ), which is the worlds most widely distributed species of gull. The herring gull breeds extensively on the coasts of large lakes, rivers, and the oceans of North America and Eurasia. It spends the non-breeding season in the southern parts of its breeding range, and as far into the tropics as the equatorial coasts of Africa, the Americas, and Southeast Asia. The taxonomy of herring gulls has engendered some controversy among ornithologists due to confusion about the identity of subspecies and whether some of these should be considered as distinct species. Herring gulls breed freely with other seemingly distinct gulls, including the Iceland gull (L. glau-coides ), Thayers gull (L. thayeri ), and even the considerably larger, glaucous gull (L. hyperboreus ).

The worlds largest gull is the great black-backed gull (L. marinus ). This large, black-mantled species breeds on the north Atlantic coasts of both North America and Europe.

The glaucous-winged gull (L. glaucescens ) is an abundant species on the west coast of North and Central America. The western gull (L. occidentalis ) is a black-backed species of the west coast of North America and is rather similar to the lesser black-backed gull (L. fuscus ) of Europe, which sometimes strays to North America during the non-breeding season.

The ring-billed gull (L. delawarensis ) is a common and widespread breeding gull, particularly on prairie lakes and on the Great Lakes, migrating to winter on the Atlantic and Pacific coasts.

The California gull (L. californicus ) breeds in large colonies on prairie lakes and winters along the Pacific coast. This is the species of gull that descended on the grasshopper-infested fields of the first Mormons in Utah, helping to save their new colony. When grasshoppers are abundant, these gulls will gorge themselves so thoroughly with these insects that they are temporarily unable to fly.

The laughing gull (L. atricilla ) breeds on the coast of the Gulf of Mexico and the Atlantic states. Like other black-headed gulls, this species has a white head, with some black spots, during the non-breeding season. Franklins gull (L. pipixcan ) is another black-headed species, breeding on small inland lakes, potholes, and marshes of the prairies, and migrating to the west coast of South America to spend the winter. Bonapartes gull (L. philadelphia ) breeds beside lakes and in other wetlands in the subarctic taiga and muskeg. This species commonly builds its nests in short spruce trees.

The black-headed gull (Larus ridibundus ) is a small, widespread European species, which has recently begun to breed in small numbers in eastern Canada, particularly in Newfoundland.

Almost all species of gulls are in the genus Larus. One exception in North America is the kittiwake (Rissa tridactyla ), a subarctic, highly colonial, cliff-nesting marine species that lacks the hind toe found in other species of gulls. The kittiwake breeds in large colonies in various places in the Canadian Arctic as well as in northern Eurasia. This species spends its non-breeding season feeding pelagically at sea, as far south as the tropics.

Another non-Larus species is Sabines gull (Xema sabini ), a fork-tailed gull that breeds in the arctic tundra of northern Canada, Greenland, Spitzbergen, and Siberia, and migrates down both the Atlantic and Pacific coasts to winter at sea off Peru and eastern South Africa. The ivory gull (Pagophila eburnea ) is a rare, all-white species that only breeds in a few small colonies in the High Arctic of Canada and Siberia.

Rosss gull (Rhodostethia rosea ) is another rare gull of the Arctic, breeding in a few places in eastern Siberia and, very rarely, at Hudson Bay in Canada. Rosss gull is a particularly beautiful small-sized gull, with bright-red legs and subtly pink breast and face plumage. On rare occasions, individuals of Rosss gull will wander to more southerly regions of North America, to the great excitement of many bird watchers.

Gulls and people

Because they are both omnivorous and opportunistic in their feeding habits, some species of gulls have benefited greatly from certain human activities. In particular, gulls often feed on an amazing repertoire of foods at garbage dumps, especially if the daily refuse has not been covered over with a layer of dirt (as it would be in a sanitary landfill). Gulls also follow fishing boats, feeding on offal and by-catch as it is discarded overboard. In addition, gulls frequently patrol recently plowed agricultural land, where they feed on worms and other invertebrates that have been exposed by disturbance of the soil.

KEY TERMS

Offal Wastes from the butchering of fish, mostly consisting of the head, spinal column with attached muscles, and the guts. Fishing boats that process their catch at sea commonly dispose of the offal by throwing it into the water.

Pelagic Refers to an animal that spends time at sea, far away from land.

These and other opportunities provided to gulls by humans have allowed a tremendous increase in the populations and ranges of some species. Gulls whose populations in North America have shown especially large increases include the herring gull, great black-backed gull, ring-billed gull, laughing gull, and glaucous-winged gull, among others.

In places where they are common, gulls are often considered to be a significant nuisance. Gulls are most commonly regarded as pests at and near solid-waste disposal sites, where they generally pick over the garbage. The can also be considered a problem in parks and stadiums, where they forage for left-over foods. In cities and towns where municipal drinking water is stored in open reservoirs, the presence of large numbers of gulls can result in fecal contamination of the water as a result of their copious defecations. Gulls are also a hazard to airplane navigation because of the risks of collisions. A single gull taken into a jet engine can easily ruin the machine and has resulted in airplane crashes. However, some species of gulls benefit humans by feeding on large numbers of insects that might otherwise damage crops.

The larger species of gulls, such as the herring and great black-backed gulls, can be formidable predators of the young of smaller seabirds. The increased populations of these predatory gulls have severely affected the breeding success and populations of some smaller species, especially terns. This is a serious conservation problem in many areas, and it may only be resolved by killing adult gulls with guns or poisons. The alternative to this unsavory control strategy would likely be the local extirpation, and perhaps even global endan-germent of, the prey species.

In many places gulls eggs are regarded as a delicacy and are collected as a subsistence food or to sell. To ensure freshness, all of the eggs in a colony are generally smashed on the first visit to the breeding site. Consequently, the age of any eggs that are collected on the second or subsequent visits is known. Adult or young gulls are also sometimes eaten by people, though this is not very common.

In spite of some of the problems with gulls, they are a favored group among bird-watchers. Numerous species of gulls can be seen in some places, especially during the non-breeding season. Birders often undertake field trips to those avian hot-spots, with the specific goal of identifying as many rare species of gulls as possible.

Resources

BOOKS

Brooke, M., and T. Birkhead. The Cambridge Encyclopedia of Ornithology. Cambridge, UK: Cambridge University Press, 1991.

Croxall, J.P., ed. Seabirds: Feeding Biology and their Role in Marine Ecosystems. Cambridge, UK: Cambridge University Press, 1987.

del Hoyo, J., A. Elliott, and J. Sargatal. Handbook of the Birds of the World. Vol. 3, Hoatzin to Auks. Barcelona: Lynx Edicions, 1996.

Grant, P.J. Gulls: An Identification Guide. Vermillion, SD: Buteo Books, 1997.

Harrison, P. Seabirds: An Identification Guide. New York: Houghton Mifflin, 1991.

Olsen, K.M., and H. Larsson. Gulls of North America, Europe, and Asia. Princeton, NJ: Princeton University Press, 2004.

Richards, A. Seabirds of the Northern Hemisphere. New York: Dragonsworld, 1990.

PERIODICALS

Krajick, K. In Search of the Ivory Gull: A Symbol of the High Arctic Has Almost Disappeared, and Scientists Are on a Quest to Understand Why. Science 301 (September 26, 2003): 18401841.

Bill Freedman

Gulls

views updated May 11 2018

Gulls

Gulls are 43 species of seabirds, in the subfamily Larinae of the family Laridae, which also includes the terns . Gulls occur in a wide range of coastal habitats, ranging from inland lakes, rivers , and wetlands , to marine shores and estuaries. Their distribution is virtually world-wide, but most species occur in the Northern Hemisphere.

Species of gulls range in body length from 8-32 in (20-81 cm). Their wings are long and pointed, and gulls have a short squared tail. The legs are short and stout, and the feet have webbing between the toes, useful for swimming. The bill is rather stout and hooked at the end.

Gulls are typically white-colored, with the wings and back, known as the "mantle," being colored gray or black. Some species have a black head during the breeding season. The sexes are alike in color and shape. Immature birds are usually much darker colored than the adults, but in a few species they are whiter.

Gulls are strong fliers, and they can undertake long-distance movements for purposes of feeding or during their migrations. Gulls often soar and glide effortlessly, whenever possible using the wind and updrafts to transport them where they want to go. Gulls are gregarious animals, both during the breeding season when they nest in loose colonies and during the non-breeding season when they often occur in large foraging and roosting flocks.

Gulls are highly omnivorous and opportunistic animals, eating a wide range of foods, depending on availability. However, they mostly feed on animal biomass , and less commonly on vegetation, especially fruits . Gulls are capable fishers, aerially spotting a fish as it
swims near the surface and catching it in their beak. This is usually done either by picking the food off the surface of the water , or sometimes by catching the prey after a head-long, shallow plunge into the water. Gulls also predate on the young of other seabirds when the opportunity presents itself. In addition, they scavenge carrion whenever it is available. Many species also scavenge the edible refuse of humans, near garbage dumps, fishing boats, fish-processing factories, and similar sorts of places.

Gulls nest in loosely structured colonies, generally building a mound-like nest out of grasses and seaweeds. Most species nest on the ground, but a few nest on ledges on cliffs. Gulls lay one to four greenish, speckled eggs, which are incubated by both sexes of the pair, which also share the raising of the young. Depending on the species, gulls can take as long as four to five years to reach sexual maturity. Some species of gulls are long-lived, and leg-ringed individuals have reached ages greater than 40 years.


Gulls in North America

The name "sea-gull" does not really apply to any particular species of bird. However, this name would be most appropriately used to describe the herring gull (Larus argentatus), which is the world's most widely distributed species of gull. The herring gull breeds extensively on the coasts of large lakes, rivers, and the oceans of North America and Eurasia. The herring gull spends its non-breeding season in the southern parts of its breeding range, and as far into the tropics as the equatorial coasts of Africa , the Americas, and Southeast Asia . The taxonomy of herring gulls has engendered some controversy among ornithologists due to confusion about the identity of subspecies and whether some of these should be considered as distinct species. Herring gulls breed freely with other seemingly distinct gulls, including the Iceland gull (L. glaucoides), Thayer's gull (L. thayeri), and even the considerably larger, glaucous gull (Larus hyperboreus).

The world's largest gull is the greater black-backed gull (L. marinus). This large, black-mantled species breeds on the north Atlantic coasts of both North America and Europe .

The glaucous-winged gull (L. glaucescens) is an abundant species on the west coast of North and Central America. The western gull (L. occidentalis) is a black-backed species of the west coast of North America and is rather similar to the lesser black-backed gull (L. fuscus) of Europe, which sometimes strays to North America during the non-breeding season.

The ring-billed gull (L. delawarensis) is a common and widespread breeding gull, particularly on prairie lakes and on the Great Lakes, migrating to winter on the Atlantic and Pacific coasts.

The California gull (L. californicus) breeds in large colonies on prairie lakes and winters along the Pacific coast. This is the species of gull that "miraculously" descended on the grasshopper-infested fields of the first Mormons in Utah, helping to save their new colony. When grasshoppers are abundant, these gulls will gorge themselves so thoroughly with these insects that they are temporarily unable to fly.

The laughing gull (L. atricilla) breeds on the coast of the Gulf of Mexico and the Atlantic states. Like other black-headed gulls, this species has a white head, with some black spots, during the non-breeding season. Franklin's gull (L. pipixcan) is another black-headed species, breeding on small inland lakes, potholes, and marshes of the prairies, and migrating to the west coast of South America to spend the winter. Bonaparte's gull (L. philadelphia) breeds beside lakes and in other wetlands in the subarctic taiga and muskeg. This species commonly builds its nests in short spruce trees.

The black-headed gull (Larus ridibundus) is a small, widespread European species, which has recently begun to breed in small numbers in eastern Canada, particularly in Newfoundland.

Almost all species of gulls are in the genus Larus. One exception in North America is the kittiwake (Rissa tridactyla), a subarctic, highly colonial, cliff-nesting marine species that lacks the hind toe found in other species of gulls. The kittiwake breeds in large colonies in various places in the Canadian Arctic as well as in northern Eurasia. This species spends its non-breeding season feeding pelagically at sea, as far south as the tropics.

Another non-Larus species is Sabine's gull (Xema sabini), a fork-tailed gull that breeds in the arctic tundra of northern Canada, Greenland, Spitzbergen, and Siberia, and migrates down both the Atlantic and Pacific coasts to winter at sea off Peru and eastern South Africa. The ivory gull (Pagophila eburnea) is a rare, all-white species that only breeds in a few small colonies in the High Arctic of Canada and Siberia.

Ross's gull (Rhodostethia rosea) is another rare gull of the Arctic, breeding in a few places in eastern Siberia and, very rarely, at Hudson Bay in Canada. Ross's gull is a particularly beautiful small-sized gull, with bright-red legs and subtly pink breast and face plumage. On rare occasions, individuals of Ross's gull will wander to more southerly regions of North America, to the great excitement of many bird watchers.


Gulls and people

Because they are both omnivorous and opportunistic in their feeding habits, some species of gulls have benefitted greatly from certain human activities. In particular, gulls often feed on an amazing repertoire of foods at garbage dumps, especially if the daily refuse has not been covered over with a layer of dirt (as it would be in a sanitary landfill ). Gulls also follow fishing boats, feeding on offal and by-catch as it is discarded overboard. In addition, gulls frequently patrol recently plowed agricultural land, where they feed on worms and other invertebrates that have been exposed by disturbance of the soil .

These and other opportunities provided to gulls by humans have allowed a tremendous increase in the populations and ranges of some species. Gulls whose populations in North America have shown especially large increases include the herring gull, great black-baked gull, ringed-bill gull, laughing gull, and glaucous-winged gull, among others.

In places where they are common, gulls are often considered to be a significant nuisance. Gulls are most commonly regarded as pests at and near solid-waste disposal sites, where they generally pick over the garbage. The can also be considered a problem in parks and stadiums, where they forage for left-over foods. In cities and towns where municipal drinking water is stored in open reservoirs, the presence of large numbers of gulls can result in fecal contamination of the water as a result of their copious defecations. Gulls are also a hazard to airplane navigation because of the risks of collisions. A single gull taken into a jet engine can easily ruin the machine and has resulted in airplane crashes. However, some species of gulls benefit humans by feeding on large numbers of insects that might otherwise damage crops .

The larger species of gulls, such as the herring and great black-backed gulls can be formidable predators of the young of smaller seabirds. The increased populations of these predatory gulls have severely affected the breeding success and populations of some smaller species, especially terns. This is a serious conservation problem in many areas, and it may only be resolved by killing adult gulls with guns or poisons. The alternative to this unsavory control strategy would likely be the local extirpation, and perhaps even global endangerment of, the prey species.

In many places gulls eggs are regarded as a delicacy and are collected as a subsistence food or to sell. To ensure freshness, all of the eggs in a colony are generally smashed on the first visit to the breeding site. Consequently, the age of any eggs that are collected on the second or subsequent visits is known. Adult or young gulls are also sometimes eaten by people, though this is not very common.

In spite of some of the problems with gulls, they are a favored group among bird-watchers. Numerous species of gulls can be seen in some places, especially during the non-breeding season. Birders often undertake field trips to those avian hot-spots, with the specific goal of identifying as many rare species of gulls as possible.


Resources

books

Brooke, M., and T. Birkhead. The Cambridge Encyclopedia of Ornithology. Cambridge, UK: Cambridge University Press, 1991.

Croxall, J.P., ed. Seabirds: Feeding Biology and their Role in Marine Ecosystems. Cambridge, UK: Cambridge University Press, 1987.

Grant, P. Gulls: A Guide to Identification. London, UK: Poyser Pubs, 1986.

Harrison, C.J.O., ed. Bird Families of the World. New York: H. N. Abrams Pubs, 1978.

Harrison, P. Seabirds: An Identification Guide. Beckenham, UK: Croom Helm, 1991.

Richards, A. Seabirds of the Northern Hemisphere. New York: Dragonsworld, 1990.


Bill Freedman

KEY TERMS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Offal

—Wastes from the butchering of fish, mostly consisting of the head, spinal column with attached muscles, and the guts. Fishing boats that process their catch at sea commonly dispose of the offal by throwing it into the water.

Pelagic

—Refers to an animal that spends time at sea, far away from land.

gull

views updated May 18 2018

gull1 / gəl/ • n. a long-winged, web-footed seabird (Larus and other genera, family Laridae) with a raucous call, typically having white plumage with a gray or black mantle.gull2 • v. [tr.] fool or deceive (someone): workers had been gulled into inflicting poverty and deprivation upon themselves.• n. a person who is fooled or deceived.

Gull

views updated May 23 2018

GULL

GULL (Heb. שַׁחַף; av "cuckow," jps "sea-mew"), bird mentioned in the Bible as prohibited as food (Lev. 11:16; Deut. 14:15), the Hebrew name means "thin" or "swift of movement" and, on the basis of its rendering as λάρος in the Septuagint, refers to the gull. Eight species of the genus Larus are found in Israel. Feeding on sea fish and scraps of food, they follow ships for the offal thrown overboard. The gull also penetrates to inland regions of the country (even to the Negev) where it lives on worms and snails. To the family of the gull (Laridae) belong the Sterna, a genus of which two species are found in Israel, distinguished from the gull by being web-footed along the entire length of their toes.

bibliography:

J. Feliks, Animal World of the Bible (1962), 86; M. Dor, Leksikon Zo'ologi (1965), 330f.

[Jehuda Feliks]

gull

views updated Jun 11 2018

gull1 (dial.) unfledged bird; gosling. XIV. prob. sb. use of †gull yellow (- ON. gulr).
Hence, perh. partly the use of gull for ‘credulous person, dupe’ (late XVI), but cf. the somewhat earlier gull vb. dupe, cheat, surviving in gullible XIX, which itself may be a transf. use of †gull vb. swallow (XVI), rel. to †gull sb. throat, gullet (XV) — OF. go(u)le (see GULLET).

gull

views updated May 29 2018

gull (seagull) Any of various ground-nesting birds found along coastlines. They eat carrion, refuse, fish, shellfish, eggs, and young birds. The herring gull (Larus argentatus) is grey and white with black markings, hooked bill, pointed wings and webbed feet. It grows to 56–66cm (22–26in). The black-headed gull (Larus ridibundus) is smaller, with black feathers on its head in summer. Family Laridae.

gull

views updated Jun 08 2018

gull2 long-winged web-footed sea-bird. XV. prob. — W. gwylan, Cornish guilan :- Celt. *voilenno-.

gulls

views updated May 18 2018

gull

views updated May 14 2018

gull a credulous person, a dupe, a fool, possibly a transferred used of the word meaning ‘an unfledged bird’.

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