Common black-headed gull (North America)
The Black-headed gull (Chroicocephalus ridibundus) is a small and one of the most abundant gulls in much of Europe and Asia, and also in eastern Canada. It displays a variety of compelling behaviors and adaptations. Some of these include removing eggshells from one's nest after hatching, begging co-ordination between siblings, differences between sexes, conspecific brood parasitism, and extra-pair paternity.
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DiurnalDiurnal animals are active during the daytime, with a period of sleeping or other inactivity at night. The timing of activity by an animal depends ...
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OmnivoreAn omnivore is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and ani...
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ScavengerScavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While sc...
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SemiaquaticSemiaquatic animals are those that are primarily or partly terrestrial but that spend a large amount of time swimming or otherwise occupied in wate...
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GlidingGliding flight is heavier-than-air flight without the use of thrust and is employed by gliding animals. Birds in particular use gliding flight to m...
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PrecocialPrecocial species are those in which the young are relatively mature and mobile from the moment of birth or hatching. Precocial species are normall...
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CongregatoryCongregatory animals tend to gather in large numbers in specific areas as breeding colonies, for feeding, or for resting.
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OviparousOviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
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TerritorialA territory is a sociographical area that which an animal consistently defends against the conspecific competition (or, occasionally, against anima...
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SeabirdSeabirds (also known as marine birds) are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, b...
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Soaring birdsSoaring birds can maintain flight without wing flapping, using rising air currents. Many gliding birds are able to "lock" their extended wings by m...
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MonogamyMonogamy is a form of relationship in which both the male and the female has only one partner. This pair may cohabitate in an area or territory for...
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FlockingFlocking birds are those that tend to gather to forage or travel collectively. Avian flocks are typically associated with migration. Flocking also ...
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ColonialColonial animals live in large aggregations composed of two or more conspecific individuals in close association with or connected to, one another....
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MigratingAnimal migration is the relatively long-distance movement of individual animals, usually on a seasonal basis. It is the most common form of migrati...
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starts withThe summer adult has a chocolate-brown head (not black, although does look black from a distance), a pale grey body, black tips to the primary wing feathers, and a red bill and legs. The hood is lost in winter, leaving just two dark spots. Immature birds have a mottled pattern of brown spots over most of the body and a black band on the tail. There is no difference in plumage between the sexes. In flight, the white leading edge to the wing is a good field mark. First-year birds have a black terminal tail band, more dark areas in the wings, and, in summer, a less fully developed dark hood.
Black-headed gulls breed in much of Europe, Asia, and in coastal eastern Canada. Most of their populations are migratory and winter further south, but some birds reside in the milder westernmost areas of Europe. Some Black-headed gulls also spend the winter in northeastern North America. They breed in large reed beds or marshes, or on islands in lakes, rivers, lagoons, deltas, and estuaries. They may also occur in ponds, canals, and flood lands, nesting on the heather moors, sand dunes, or beaches. During the winter these birds are found in estuaries with sandy or muddy beaches, ploughed fields, moist grasslands, reservoirs, urban parks, farmland, and gardens.
Black-headed gulls are highly gregarious birds, both when feeding or in evening roosts; they also breed in colonies. They are rarely seen at sea far from coasts. Black-headed gulls are active during the day and feed mainly by taking prey from the surface while swimming, or by dipping the head under the surface. They also walk along the coasts and probe for aquatic prey or catch flying insects on the wings. Black-headed birds are noisy, especially in colonies, with a familiar "kree-ar" call. When feeding they utter a sharp “kek-kek”.
Black-headed gulls are monogamous breeders. This means that males will mate with only one female and females will mate with only one male. The breeding season usually starts in late March; during this time pairs become very territorial and defend their nests vigorously. Black-headed gulls nest in big colonies and build their nests on the ground in low vegetation close to each other. Females lay 1 to 3 eggs and both parents incubate them within 22-26 days. The chicks are precocial; they are hatched with eyes open and are covered in down. They are able to stand within a day, but usually stay in the nest for a week and are fed by both parents. The chicks fledge about 35 days after hatching and become reproductively mature when they are 2 years old.
Black-headed gulls don't face any significant threats at present, however, they do suffer from diseases such as avian influenza and avian botulism, from egg collection and chemical pollutants.
According to the IUCN Red List, the total Black-headed gull population size is around 4,800,000-8,900,000 individuals. National population estimates include more than 1,000 individuals on migration and more than 1,000 wintering individuals in China; 1,000-10,000 individuals on migration and more than 1,000 wintering individuals in Taiwan; more than 1,000 individuals on migration and more than 1,000 wintering individuals in Korea; less than 10,000 individuals on migration and 1,000-10,000 wintering individuals in Japan and 10,000-1 million breeding pairs and more than 1,000 individuals on migration in Russia. Currently, this species is classified as Least Concern (LC) on the IUCN Red List.
Social animals are those animals that interact highly with other animals, usually of their own species (conspecifics), to the point of having a rec...