This is an accepted version of this page
48-547: Larus modestus The grey gull , also known as garuma gull ( Leucophaeus modestus ) is a medium-sized gull native to South America . Unusual among gulls, it breeds inland in the extremely dry Atacama Desert in northern Chile , although it is present as a non-breeding bird along much of the Pacific coast of South America. The sexes are similar in grey gulls. Adults grow to a length of about 45 cm (18 in) and weigh some 360 to 400 g (13 to 14 oz). The head
96-450: A behaviour seen in other animal species, such as elephants, wolves, and the fathead minnow . Lasting between 22 and 26 days, incubation begins after the first egg is laid but is not continuous until after the second egg is laid, meaning that the first two chicks hatch at about the same time, and the third some time later. Young chicks are brooded by their parents for about one or two weeks, and often at least one parent stays behind to guard
144-495: A few species do live on islands such as the Galapagos and New Caledonia . Many species breed in coastal colonies, with a preference for islands, and one species, the grey gull , breeds in the interior of dry deserts far from water. Considerable variety exists in the family and species may breed and feed in marine, freshwater, or terrestrial habitats. Most gull species are migratory , with birds moving to warmer habitats during
192-498: A higher level of synchronisation in larger colonies. The eggs of gulls are usually dark tan to brown or dark olive with dark splotches and scrawl markings, and they are well camouflaged. Both sexes incubate the eggs; incubation bouts last between one and four hours during the day, and one parent incubates through the night. Research on various bird species, including gulls, suggests that females form pair bonds with other females to obtain alloparental care for their dependent offspring,
240-534: A mixture of both natural prey and human refuse. The gulls relied substantially on the Henslow's swimming crab ( Polybius henslowii ). Yet, in times when local prey availability is low, the gulls shift to human-related food. These temporal shifts from a marine to terrestrial prey highlight the resilience adult gulls have and their ability to keep chick condition consistent. Human disturbance has also shown to have an effect on gull breeding, in which hatching failure
288-569: A number of years after the break-up. Gulls also display high levels of site fidelity , returning to the same colony after breeding there once and even usually breeding at the same location within that colony. Gull colonies can vary from just a few pairs to over a hundred thousand pairs, and may be exclusive to that gull species or shared with other seabird species. A few species nest singly, and single pairs of band-tailed gulls may breed in colonies of other bird species. Within colonies, gull pairs are territorial , defending an area of varying size around
336-410: A red spot for the larger white-headed species and red, dark red or black in the smaller species. Gulls are a generalist species that can thrive in various environments and survive on a widely varied diet. They are the least specialised of all the seabirds, and their morphology allows for equal adeptness in swimming, flying, and walking. They are more adept walking on land than most other seabirds, and
384-509: A study of cutthroat trout stocking, researchers found that the addition of this piscivore can have noticeable effects on non-aquatic organisms, in this case bats feeding on insects emerging from the water with the trout. Another study done on lionfish removal to maintain low densities used piscivore densities as a biological indicator for coral reef success. There exist classifications of primary and secondary piscivores. Primary piscivores, also known as "specialists", shift to this habit in
432-560: A suitable surface on which to drop shells, and apparently a learned component to the task exists, as older birds are more successful than younger ones. While overall feeding success is a function of age, the diversity in both prey and feeding methods is not. The time taken to learn foraging skills may explain the delayed maturation in gulls. Gulls have only a limited ability to dive below the water to feed on deeper prey. To obtain prey from deeper down, many species of gulls feed in association with other animals, where marine hunters drive prey to
480-544: Is a carnivorous animal that primarily eats fish . The name piscivore is derived from Latin piscis 'fish' and vorō 'to devour'. Piscivore is equivalent to the Greek-derived word ichthyophage , both of which mean "fish eater". Fish were the diet of early tetrapod evolution (via water-bound amphibians during the Devonian period); insectivory came next; then in time,
528-427: Is a layperson's term and is not used by most ornithologists and biologists. The name is used informally to refer to a common local species (or all gulls in general) and has no fixed taxonomic meaning. In common usage, gull-like seabirds that are not technically gulls (e.g. albatrosses , fulmars , terns , and skuas ) may also be referred to as 'seagulls' by the layperson. The American Ornithologists' Union combines
SECTION 10
#1732802489205576-516: Is a list of the 54 gull species , presented in taxonomic sequence . The Laridae are known from not-yet-published fossil evidence since the Early Oligocene , some 30–33 million years ago. Three gull-like species were described by Alphonse Milne-Edwards from the early Miocene of Saint-Gérand-le-Puy, France. A fossil gull from the Middle to Late Miocene of Cherry County, Nebraska , US,
624-468: Is a single-prey specialist, and no gull species forages using only a single method. The type of food depends on circumstances, and terrestrial prey such as seeds, fruit, and earthworms are more common during the breeding season while marine prey is more common in the nonbreeding season when birds spend more time on large bodies of water. In addition to taking a wide range of prey, gulls display great versatility in how they obtain prey. Prey can be obtained in
672-401: Is an important part of the pair-bonding process. Most gull nests are mats of herbaceous matter with a central nest cup. Nests are usually built on the ground, but a few species establish their nests on cliffs (the usual preference for kittiwakes), and some choose to nest in trees and high places (e.g. Bonaparte's gulls ). Species that nest in marshes need to construct a nesting platform to keep
720-479: Is believed to be downwards. However, the total number of birds is sufficiently large to justify listing the grey gull as being of " least concern " rather than including it in a more threatened category. Gull 11, see below Gulls , or colloquially seagulls , are seabirds of the family Laridae in the suborder Lari . They are most closely related to terns and skimmers , distantly related to auks , and even more distantly related to waders . Until
768-423: Is darker varies from pale grey to black. A few species vary in this, the ivory gull is entirely white, and some like the lava gull and Heermann's gull have partly or entirely grey bodies. The wingtips of most species are black, which improves their resistance to wear and tear, usually with a diagnostic pattern of white markings. The head of a gull may be covered by a dark hood or be entirely white. The plumage of
816-419: Is directly proportional to the amount of disturbance in a given plot. Certain gull breeds have been known to feast on the eyeballs of baby seals, and directly pilfer milk from the elephant seal 's teat. Gulls are monogamous and colonial breeders that display mate fidelity which normally lasts for the life of the pair. Divorce of mated pairs does occur, but it apparently has a social cost that persists for
864-610: Is placed in the prehistoric genus Gaviota ; apart from this and the undescribed Early Oligocene fossil, all prehistoric species were tentatively assigned to the modern genus Larus . Among those of them that have been confirmed as gulls, Milne-Edwards' "Larus" elegans and "L." totanoides from the Late Oligocene/ Early Miocene of southeast France have since been separated in Laricola . Piscivore A piscivore ( / ˈ p ɪ s ɪ v ɔːr / )
912-464: Is questionable. Before the 21st century, most gulls were placed in the genus Larus , but this arrangement is now known to be polyphyletic , leading to the resurrection of the genera Ichthyaetus , Chroicocephalus , Leucophaeus , Saundersilarus , and Hydrocoloeus . Some English names refer to species complexes within the group: In common usage, members of various gull species are often referred to as 'sea gulls' or 'seagulls'; however, this
960-469: Is white in summer but brownish-grey in winter. The body and wings are grey with the dorsal surface rather darker than the ventral region. The flight feathers are black and the inner primaries and the secondaries have white tips, visible in flight. The tail has a band of black with a white trailing edge. The legs and beak are black and the iris is brown. The call is similar to that of the laughing gull ( Leucophaeus atricilla ). The grey gull breeds inland in
1008-745: The Atacama Desert in northern Chile. Its non-breeding range includes s. Ecuador, Peru through south-central Chile, and it has been recorded in the Falkland Islands, South Georgia and the South Sandwich Islands. It is a vagrant to Mexico, the Galapagos, Guatemala, Brazil, Argentina, Panama and Florida; an earlier report of it in Louisiana, from 1987, has not been accepted by a birdwatching authority. For many years, it
SECTION 20
#17328024892051056-800: The Sternidae , Stercorariidae , and Rhynchopidae as subfamilies in the family Laridae, but early 21st-century research shows this to be incorrect. A molecular phylogenetic study published in 2022 found the following relationships between the genera, including the most recent generic change: the placement of Saunders's gull in its own genus Saundersilarus . Creagrus – swallow-tailed gull Hydrocoloeus – little gull Rhodostethia – Ross's gull Rissa – kittiwakes (2 species) Xema – Sabine's gull Pagophila – ivory gull Saundersilarus – Saunders's gull Chroicocephalus – (10 species) Leucophaeus – (5 species) Ichthyaetus – (6 species) Larus – (24 species) This
1104-495: The bulldog bat and gharial , are strictly dependent on fish for food. Some creatures, including cnidarians , octopuses , squid , cetaceans , spiders , grizzly bears , jaguars , wolves , snakes , turtles and sea gulls , may have fish as significant if not dominant portions of their diets. Humans can live on fish-based diets , as can their carnivorous domesticated pets such as dogs and cats . The ecological effects of piscivores can extend to other food chains. In
1152-531: The kittiwakes and Sabine's gull . The large species take up to four years to attain full adult plumage, but two years is typical for small gulls. Large white-headed gulls are usually long-lived birds, with a maximum age of 49 years recorded for the herring gull . Gulls nest in large, densely packed, noisy colonies. They lay two or three speckled eggs in nests composed of vegetation. The young are precocial , born with dark mottled down and mobile upon hatching. Gulls are resourceful, inquisitive, and intelligent,
1200-512: The 21st century, most gulls were placed in the genus Larus , but that arrangement is now considered polyphyletic , leading to the resurrection of several genera. An older name for gulls is mews ; this still exists in certain regional English dialects and is cognate with German Möwe , Danish måge , Swedish mås , Dutch meeuw , Norwegian måke/måse , and French mouette . Typically medium to large in size, gulls are usually grey or white, often with black markings on
1248-420: The air, on water, or on land. In the air, a number of hooded species are able to hawk insects on the wing; larger species perform this feat more rarely. Gulls on the wing also snatch items both off water and off the ground, and over water they also plunge-dive to catch prey. Again, smaller species are more manoeuvrable and better able to hover-dip fish from the air. Dipping is also common when birds are sitting on
1296-472: The black-backed gull) was heavily impacted by human fishing discards and fishing ports. Looking further at environmental drivers that structure bird habitat and distribution are human and climate impacts. Looking at waterbird distribution in wetlands, changes in salinity, water depth, water body isolation and hydroperiod altered bird community structure in both a species and guild specific way. Gulls in particular had high associations with salinity levels, being
1344-586: The chicks until they fledge . Although the chicks are fed by both parents, early on in the rearing period the male does most of the feeding and the female most of the brooding and guarding. The family Laridae was introduced (as Laridia) by the French polymath Constantine Samuel Rafinesque in 1815. The taxonomy of gulls is confused by their widespread distribution zones of hybridisation leading to gene flow . Some have traditionally been considered ring species , but research has suggested that this assumption
1392-411: The coast. Once the eggs hatch, the parents take it in turn to make the round trip to the sea to bring food and water to their offspring. The humidity, wind speed, air and surface temperatures vary widely on a daily basis and the gull has to use various thermo-regulatory mechanisms when nesting to maintain its body temperature and that of its eggs and chicks within acceptable limits. In the hottest part of
1440-411: The coasts near their breeding sites. A big influence on non-breeding gull distribution are food patches. Human fisheries especially have an impact since they often provide an abundant and predictable food resource. Looking at two species of gulls dependent on human fisheries, Audouin's gull ( Ichthyaetus audouinii ) and lesser black-backed gulls ( Larus fuscus) , their breeding distributions (especially
1488-604: The day the parent bird stands over its nest to prevent the eggs or chicks overheating. Its chief predator is the turkey vulture ( Cathartes aura ) and when threatened, the incubating parent sometimes leaves the nest temporarily, and when this happens the eggs need to have impervious shells in order to avoid losing too much water through evaporation. In fact, the evaporative loss from the eggs is found to be about one third of that which occurs in Heermann's gull ( Larus heermanni ), another desert nesting species. The typical habitat of
Grey gull - Misplaced Pages Continue
1536-400: The exceptions being Sabine's gull and swallow-tailed gulls , which have forked tails, and Ross's gull , which has a wedge-shaped tail. Gulls have moderately long legs, especially when compared to the similar terns, with fully webbed feet. The bill is generally heavy and slightly hooked, with the larger species having stouter bills than the smaller species. The bill colour is often yellow with
1584-695: The first few months of their lives. Secondary piscivores will move to eating primarily fish later in their lifetime. It is hypothesized that the secondary piscivores' diet change is due to an adaptation to maintain efficiency in their use of energy while growing. Numerous extinct and prehistoric animals are hypothesized to have been primarily piscivorous due to anatomy and/or ecology. Furthermore, some have been confirmed to be piscivorous through fossil evidence. This list includes specialist piscivores, such as Laganosuchus , as well as generalist predators, such as Baryonyx and Spinosaurus , found to have or assumed to have eaten fish. This ecology -related article
1632-423: The grey gull is sandy beaches and mudflats along the western coasts of South America where it probes with its beak in the sediment for invertebrate prey, particularly mole crabs . It also eats fish and ragworms , scavenges for offal and sometimes follows fishing boats. The grey gull has a restricted inland breeding range and a limited wintering range along the coasts of Ecuador, Peru and Chile. The population trend
1680-549: The head or wings. They normally have harsh wailing or squawking calls; stout, longish bills; and webbed feet. Most gulls are ground-nesting piscivores or carnivores which take live food or scavenge opportunistically, particularly the Larus species. Live food often includes crustaceans , molluscs , fish and small birds. Gulls have unhinging jaws that provide the flexibility to consume large prey. Gulls are typically coastal or inland species, rarely venturing far out to sea, except for
1728-422: The head varies by breeding season; in nonbreeding dark-hooded gulls, the hood is lost, sometimes leaving a single spot behind the eye, and in white-headed gulls, nonbreeding heads may have streaking. The gulls have a worldwide cosmopolitan distribution . They breed on every continent, including the margins of Antarctica , and are found in the high Arctic as well. They are less common on tropical islands, although
1776-607: The larger species in particular, demonstrating complex methods of communication and a highly developed social structure. For example, many gull colonies display mobbing behaviour, attacking and harassing predators and other intruders. Certain species, such as the herring gull, have exhibited tool-use behaviour, for example using pieces of bread as bait with which to catch goldfish . Many species of gulls have learned to coexist successfully with humans and thrive in human habitats. Others rely on kleptoparasitism to get their food. Gulls have been observed preying on live whales, landing on
1824-703: The main environmental predictor for waterbird assemblage. Charadriiform birds drink salt water, as well as fresh water, as they possess exocrine glands located in supraorbital grooves of the skull by which salt can be excreted through the nostrils to assist the kidneys in maintaining electrolyte balance. Gulls are highly adaptable feeders that opportunistically take a wide range of prey. The food taken by gulls includes fish and marine and freshwater invertebrates, both alive and already dead; terrestrial arthropods and invertebrates such as insects and earthworms; rodents, eggs, carrion, offal , reptiles, amphibians, seeds, fruit, human refuse, and even other birds. No gull species
1872-452: The more terrestrially adapted reptiles and synapsids evolved herbivory . Almost all predatory fishes (most sharks , tuna , billfishes , pikes etc.) are obligated piscivores. Some non-piscine aquatic animals , such as whales , sea lions , and crocodilians , are not completely piscivorous; often also preying on invertebrates , marine mammals , waterbirds and even wading land animals in addition to fish, while others, such as
1920-463: The nest dry, particularly species that nest in tidal marshes . Both sexes gather nesting material and build the nest, but the division of labour is not always exactly equal. In coastal towns, many gulls nest on rooftops and can be observed by nearby human residents. Clutch size is typically three eggs, although some of the smaller gulls only lay two, and the swallow-tailed gull produces a single egg. Birds synchronise their laying within colonies, with
1968-677: The nesting site from others of their species. This area can be as large as a 5-metre radius around the nest in the herring gull to just a tiny area of cliff ledge in the kittiwakes . Most gulls breed once a year and have predictable breeding seasons lasting for three to five months. Gulls begin to assemble around the colony for a few weeks prior to occupying it. Existing pairs re-establish their pair-bonds , and unpaired birds begin courting. Pairs then move back into their territories, and new males establish new territories and attempt to court females. Gulls defend their territories from rivals of both sexes using calls and aerial attacks. Nest building
Grey gull - Misplaced Pages Continue
2016-577: The northwest coast of Spain revealed a shift from a sardine to crustacean-based diet. This shift was linked to higher fishing efficiency and thus overall fish stock depletion. Lastly, closure of nearby open-air landfills limited food availability for the gulls, furthering creating a stress on their shift in diet. Between the years of 1974–1994, yellow-legged gull populations in Berlenga Island, Portugal, increased from 2600 to 44,698 individuals. Analyzing both adult and chick remains, researchers found
2064-399: The smaller gulls tend to be more manoeuvrable while walking. The walking gait of gulls includes a slight side to side motion, something that can be exaggerated in breeding displays. In the air, they are able to hover and they are also able to take off quickly with little space. The general pattern of plumage in adult gulls is a white body with a darker mantle; the extent to which the mantle
2112-462: The surface when hunting. Examples of such associations include four species of gulls feeding around plumes of mud brought to the surface by feeding grey whales , and also between orcas (largest dolphin species) and kelp gulls (and other seabirds). Looking at the effect of humans on gull diet, overfishing of target prey such as sardines have caused a shift in diet and behaviour. Analysis of yellow-legged gull's ( Larus michahellis ) pellets off
2160-448: The water, and gulls may swim in tight circles or foot paddle to bring marine invertebrates up to the surface. Food is also obtained by searching the ground, often on the shore among sand, mud or rocks. Larger gulls tend to do more feeding in this way. In shallow water gulls may also engage in foot paddling. One method of obtaining prey involves dropping heavy shells of clams and mussels onto hard surfaces. Gulls may fly some distance to find
2208-444: The whale as it surfaces and pecking out pieces of flesh. Gulls range in size from the little gull , at 120 grams ( 4 + 1 ⁄ 4 ounces) and 29 centimetres ( 11 + 1 ⁄ 2 inches), to the great black-backed gull , at 1.75 kg (3 lb 14 oz) and 76 cm (30 in). They are generally uniform in shape, with heavy bodies, long wing, and moderately long necks. The tails of all but three species are rounded;
2256-460: The winter, but the extent to which they migrate varies by species. Some migrate long distances, notably Sabine's gull , which migrates from the Arctic coasts to winter off the west coasts of South America and southern Africa, and Franklin's gull , which migrates from Canada to wintering grounds off the west coast of South America. Other species move much shorter distances and may simply disperse along
2304-433: Was a mystery as to where this bird breeds because no coastal colonies had been identified. However, in 1945, it was discovered that it bred in the Atacama Desert in the interior of Chile. This hot and arid environment has few predators and may be relatively safe for the breeding gulls. The site chosen for the nest, a scrape in the sand and often near rocks, is a waterless region some 35 to 100 km (22 to 62 mi) from
#204795