Lava gull | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Charadriiformes |
Family: | Laridae |
Genus: | Leucophaeus |
Species: | L. fuliginosus |
Binomial name | |
Leucophaeus fuliginosus (Gould, 1841) | |
Synonyms | |
Larus fuliginosus |
The lava gull (Leucophaeus fuliginosus), also known as the dusky gull, [2] is a medium-sized gull and a member of the "hooded gull" group. It is most closely related to the Laughing gull and Franklin's gull [3] and is the rarest gull in the world. It is endemic to the Galapagos Islands.
First described by John Gould in 1841 from a specimen collected on Santiago Island in the Galápagos. The species is sometimes placed in the genus Larus . It is possibly closely related to the laughing gull. [2]
The lava gull is a distinctive gull, 51 to 55 cm (20–22 in) and weighs 380 g (13 oz). The adult plumage consists of a sooty brown to black head, which unlike other dark hooded gulls doesn't vary by season. The wings are dark gray with a contrasting white line on the leading edge, thought to play a function in displays and camouflage. Its dark gray body contrasts with a paler gray belly. The uppertail is white and grey lower down. The bill and legs are black, and the inside of the mouth is scarlet. It has white upper and lower eyebrows, with red lids. Immature gulls are generally dark brown. [2]
The entire population lives on the Galapagos Islands where it is found predominantly on the islands of Santa Cruz, Isabela, San Cristobal and Genovesa. Previously its population was estimated at 300–400 pairs; [4] this estimate was revised downwards to 300-600 individuals in 2015. [5] It is currently considered the rarest gull in the world. [2]
Unlike most gulls which nest close together and sometimes touching, lava gulls are solitary nesters, rarely nesting closer than 100 meters apart. They are highly territorial, defending breeding territories of roughly 2000 sq. meters (70 m diameter) from conspecifics. They nest on the ground, often under the protection of coastal vegetation, and line the nest with plant material. They lay two olive-colored and well-camouflaged eggs that take 32 days to incubate. They generally nest close to calm water, often near lagoons. Breeding appears to be opportunistic and is not restricted to a single season. Young birds fledge at 55 days and continue to be cared for by the adults for several weeks. [2]
They are omnivores like most Larus gulls, generally scavenging or stealing from nests and from fishers, but will also catch fish, small crustaceans, and newly hatched lizards, iguanas, and turtles. They also feed on sea lion placenta. On Genovesa they exploit the kleptoparasitic behavior of the Magnificent frigatebird, capitalizing on the botched attempts by these frigatebirds to steal fish from various nesting seabirds. Potential nest predators include owls, frigatebirds and other lava gulls, as well as introduced mammals. [2]
The lava gull is categorized as "vulnerable" by the IUCN Red List because it exists in small numbers and though the population is stable, it faces numerous threats. [2]
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, 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, which is cognate with German Möwe, Danish måge, Swedish mås, Dutch meeuw, Norwegian måke/måse and French mouette, and can still be found in certain regional dialects.
The black-headed gull is a small gull that breeds in much of the Palearctic including Europe and also in coastal eastern Canada. Most of the population is migratory and winters further south, but some birds reside in the milder westernmost areas of Europe. Small numbers also occur in northeastern North America, where it was formerly known as the common black-headed gull. As is the case with many gulls, it was previously placed in the genus Larus.
The laughing gull is a medium-sized gull of North and South America. Named for its laugh-like call, it is an opportunistic omnivore and scavenger. It breeds in large colonies mostly along the Atlantic coast of North America, the Caribbean, and northern South America. The two subspecies are L. a. megalopterus — which can be seen from southeast Canada down to Central America — and L. a. atricilla, which appears from the West Indies to the Venezuelan islands. The laughing gull was long placed in the genus Larus until its present placement in Leucophaeus, which follows the American Ornithologists' Union.
The great black-backed gull is the largest member of the gull family. Described by the Cornell Lab of Ornithology 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 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.
The yellow-legged gull is a large gull found in Europe, the Middle East and North Africa, which has only recently achieved wide recognition as a distinct species. It was formerly treated as a subspecies of either the Caspian gull L. cachinnans, or more broadly as a subspecies of the herring gull L. argentatus. The genus name is from Latin Larus which appears to have referred to a gull or other large seabird, and the species name honours the German zoologist Karl Michahelles.
Franklin's gull is a small gull. The genus name Leucophaeus is from Ancient Greek leukos, "white", and phaios, "dusky". The specific pipixcan is a Nahuatl name for a type of gull.
The red-billed gull, also known as tarāpunga and once also known as the mackerel gull, is a native of New Zealand, being found throughout the country and on outlying islands including the Chatham Islands and subantarctic islands. It was formerly considered a separate species but is now usually treated as a subspecies of the silver gull.
The grey-headed gull, also known as the gray-hooded gull, is a small species of gull which breeds patchily in South America and Africa south of the Sahara. It is not truly migratory, but is more widespread in winter. This species has occurred as a rare vagrant to North America, Italy and Spain. As is the case with many gulls, it has traditionally been placed in the genus Larus.
The silver gull is the most common gull of Australia. It has been found throughout the continent, but particularly at or near coastal areas. It is smaller than the Pacific gull, which also lives in Australia.
Heermann's gull is a gull resident in the United States, Mexico and extreme southwestern British Columbia, nearly all nesting on Isla Rasa in the Gulf of California. They are usually found near shores or well out to sea, very rarely inland. The species is named after Adolphus Lewis Heermann, nineteenth-century explorer and naturalist.
The Galápagos hawk is a large hawk endemic to most of the Galápagos Islands.
The great frigatebird is a large seabird in the frigatebird family. There are major nesting populations in the tropical Pacific Ocean, such as Hawaii and the Galápagos Islands; in the Indian Ocean, colonies can be found in the Seychelles and Mauritius, and there is a tiny population in the South Atlantic, mostly on and around St. Helena and Boatswain Bird Island.
The relict gull or Central Asian gull is a medium-sized gull. It was believed to be an eastern race of the Mediterranean gull until 1971 and was traditionally placed in the genus Larus.
The swallow-tailed gull is an equatorial seabird in the gull family, Laridae. It is the only species in the genus Creagrus, which derives from the Latin Creagra and the Greek kreourgos which means butcher, also from kreas, meat; according to Jobling it would mean "hook for meat" referring to the hooked bill of this species. It was first described by French naturalist and surgeon Adolphe-Simon Neboux in 1846. Its scientific name is originally derived from the Greek word for gull, "Glaros" and via Latin Larus, "gull" and furca "two-tined fork". It spends most of its life flying and hunting over the open ocean. The main breeding location is in the Galápagos Islands, particularly the rocky shores and cliffs of Hood, Tower and Wolf Islands, with lower numbers on most of the other islands. It is more common on the eastern islands where the water is warmer.
The grey gull, also known as garuma gull 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 black-billed gull, Buller's gull, or tarāpuka (Māori) is a Near Threatened species of gull in the family Laridae. This gull is found only in New Zealand, its ancestors having arrived from Australia around 250,000 years ago.
The brown-hooded gull is a species of gull found in Argentina, Brazil, Chile, the Falkland Islands, and Uruguay. Its specific epithet, maculipennis, means 'spotted wings'. It is a white bird with a brown head and red beak and feet.
The term seabird is used for many families of birds in several orders that spend the majority of their lives at sea. Seabirds make up some, if not all, of the families in the following orders: Procellariiformes, Sphenisciformes, Pelecaniformes, and Charadriiformes. Many seabirds remain at sea for several consecutive years at a time, without ever seeing land. Breeding is the central purpose for seabirds to visit land. The breeding period is usually extremely protracted in many seabirds and may last over a year in some of the larger albatrosses; this is in stark contrast with passerine birds. Seabirds nest in single or mixed-species colonies of varying densities, mainly on offshore islands devoid of terrestrial predators. However, seabirds exhibit many unusual breeding behaviors during all stages of the reproductive cycle that are not extensively reported outside of the primary scientific literature.
Barbara Kathleen Snow, was a noted English ornithologist and a trained geologist. She and her husband, David Snow, formed a close team, becoming among the most influential British ornithologists of the 20th century.