Saunders's gull

Saunders's gull or the Chinese black-headed gull[1] (Chroicocephalus saundersi) is a species of gull in the family Laridae. It is found in China, Hong Kong, Japan, North Korea, South Korea, Macau, Russia, Taiwan, and Vietnam.[1] Its natural habitats are estuarine waters and intertidal marshes. As with many other gulls, it has traditionally been placed in the genus Larus, but based on phylogenetic work some have moved it to Chroicocephalus, while others argue it is sufficiently distinct for placement in the monotypic Saundersilarus.[2] It is threatened by habitat loss. One of its few remaining strongholds are the Yancheng Coastal Wetlands, which hosts about 20% of the world's population.

The Saunders's gull is named after the British ornithologist Howard Saunders.[3]

Saunders's gull
Saunders's Gull - Hong Kong 2
summer plumage
Saunders's Gull - Hong Kong 7
winter plumage
both at the Mai Po wetlands, Hong Kong
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Charadriiformes
Family: Laridae
Genus: Chroicocephalus
Species:
C. saundersi
Binomial name
Chroicocephalus saundersi
(Swinhoe, 1871)
Synonyms

Larus saundersi
Saundersilarus saundersi

Description

This is a very small species of gull with a length of just 33 cm (13 in) and, among gulls, only the little gull is smaller. Adults have a black hood and nape during the breeding season.[4] It is very pale with a white body, pale grey wings and a narrow black tail band.The legs and short bill are black and the body is squat. Non-breeding birds have a mottled grey hood and nape, and white-tipped wings with black markings on the primaries.[5]

Distribution and habitat

Saunders's gull breeds in eastern China and the west coast of Korea. It breeds in saltmarshes dominated by the seepweed (Suaeda glauca). It overwinters in southern China, Hong Kong, Macau, Taiwan, South Korea, southwestern Japan and Vietnam. Its winter habitats are estuaries and aquaculture ponds and some populations move inland to lakes and marshes.[5]

Biology

Saunders's gull catches its prey by flying above the ground at about ten metres (yards) and dropping swiftly on any suitable prey it finds. In this way it catches mudskippers, crabs, fish and worms. It is also a kleptoparasite, stealing food items from other species of birds. It is a poor swimmer, having only partially webbed feet, and usually stays on land, moving up the beach in front of the rising tide.[5]

It breeds in saltmarshes, its nest being a simple scrape in the ground. The birds are monogamous and each pair occupies a territory. Two or three eggs are laid in May and incubation takes about 22 days. Adults and young birds leave for their winter quarters in October.[5]

Status

The total population of this gull is estimated as being 21,000 to 22,000 individuals and seems to be in decline. The IUCN has rated it as "Vulnerable". The main threats it faces are the degradation of its habitat as it is very dependent on saltmarshes dominated by seepweed. In China, Taiwan, South Korea, Japan and elsewhere, saltmarshes are being drained to make way for aquaculture. The introduction of the strong-growing smooth cordgrass (Spartina alterniflora) has also had deleterious effects. The disturbance of adults also results in greater predation on the eggs and chicks.[1]

References

  1. ^ a b c d BirdLife International (2012). "Larus saundersi". IUCN Red List of Threatened Species. Version 2013.1. International Union for Conservation of Nature. Retrieved 2013-12-11.
  2. ^ Pons, J.-M.; Hassanin, A.; Crochet, P.-A. (2005). "Phylogenetic relationships within the Laridae (Charadriiformes: Aves) inferred from mitochondrial markers". Molecular Phylogenetics and Evolution. 37 (3): 686–699. doi:10.1016/j.ympev.2005.05.011.
  3. ^ Jobling, James A. (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. p. 348. ISBN 978-1-4081-2501-4.
  4. ^ Birdlife International
  5. ^ a b c d "Saunder's gull (Larus saundersi)". ARKive. Archived from the original on 2013-12-16. Retrieved 2013-12-12.

External links

Andean gull

The Andean gull (Chroicocephalus serranus) is a species of gull in the family Laridae. As is the case with many gulls, it has traditionally been placed in the genus Larus.

It is found in the Andes in mountainous regions of Argentina, Bolivia, Chile, Colombia, Ecuador, and Peru. It is unusual for a gull in that it breeds inland in mountain areas. It may be variously found around rivers, freshwater lakes, saline marshes, and pastureland.

Bonaparte's gull

Bonaparte's gull (Chroicocephalus philadelphia) is a member of the gull family Laridae found mainly in northern North America. At 28 to 38 cm (11 to 15 in) in length, it is one of the smallest species of gull. Its plumage is mainly white with grey upperparts. During breeding season, Bonaparte's gull gains a slate-grey hood. The sexes are similar in appearance.

Brown-headed gull

The brown-headed gull (Chroicocephalus brunnicephalus) is a small gull which breeds in the high plateaus of central Asia from Tajikistan to Ordos in Inner Mongolia. It is migratory, wintering on the coasts and large inland lakes of the Indian Subcontinent. As is the case with many gulls, was traditionally placed in the genus Larus.

This gull breeds in colonies in large reedbeds or marshes, or on islands in lakes, nesting on the ground. Like most gulls, it is highly gregarious in winter, both when feeding or in evening roosts. It is not a pelagic species, and is rarely seen at sea far from coasts.

This is a bold and opportunist feeder, which will scavenge in towns or take invertebrates in ploughed fields with equal relish.

The brown-headed gull is slightly larger than black-headed gull. The summer adult has a pale brown head, lighter than that of black-headed, a pale grey body, and red bill and legs. The black tips to the primary wing feathers have conspicuous white "mirrors". The underwing is grey with black flight feathers. The brown hood is lost in winter, leaving just dark vertical streaks.

This bird takes two years to reach maturity. First year birds have a black terminal tail band, more dark areas in the wings, and, in summer, a less homogeneous hood.

This is a noisy species, especially at colonies.

Brown-hooded gull

The brown-hooded gull (Chroicocephalus maculipennis) is a species of gull found in Argentina, Brazil, Chile, the Falkland Islands, and Uruguay. Its specific epithet, maculipennis, means 'spotted wings' (macula + penna). It is a white bird with a brown head and red beak and feet.

Chroicocephalus

Chroicocephalus is a genus of medium to relatively small gulls which were included in the genus Larus until recently. Some authorities also include the Saunders's gull in Chroicocephalus. The genus name Chroicocephalus is from Ancient Greek khroizo, "to colour", and kephale, "head".Representatives of this genus are found in regions/subregions all over the world, each species usually being confined to a region.

Franklin's gull

The Franklin's gull (Leucophaeus pipixcan) is a small (length 12.6–14.2 in, 32–36 cm) 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.

Gelochelidon

Gelochelidon is a genus of terns. It was recently considered a monotypic genus, but the Australian tern was split from the gull-billed tern.

Glaucous-winged gull

The glaucous-winged gull (Larus glaucescens) is a large, white-headed gull. The genus name is from Latin Larus which appears to have referred to a gull or other large seabird. The specific glaucescens is New Latin for "glaucous" from the Ancient Greek, glaukos. English "Glaucous" denotes a bluish-green or grey colour.

Huahine gull

The Huahine gull (Chroicocephalus utunui), also known as the Society Islands gull, is an extinct bird, a species of gull of which subfossil bones were found at the Fa'ahia archeological site on Huahine, in the Society Islands of French Polynesia.

The site is an early Polynesian occupation site dating to between 700 CE and 1200 CE, containing, as well as anthropogenic material, the remains of many species of birds now either globally or locally extinct, that were killed for their flesh, bones or feathers. The gull was described (as Larus utunui) from 12 bones from two individual birds. Osteological similarities suggest that the nearest living relative of the Huahine gull is the silver gull (C. novaehollandiae), the nearest extant populations of which are in New Zealand, 3,800 km south-west of Huahine.

Ichthyaetus

Ichthyaetus is a genus of gulls. The genus name is from Ancient Greek ikhthus, "fish", and aetos, "eagle". They were previously included in the genus Larus.

Leucophaeus

Leucophaeus is a small genus of medium-sized New World gulls, most of which are dark in plumage, usually with white crescents above and below the eyes. They were placed in the genus Larus until recently. The genus name Leucophaeus is from Ancient Greek leukos, "white", and phaios, "dusky".

Mai Po Marshes

Mai Po Marshes (Chinese: 米埔濕地; Hong Kong Hakka: Mi3bu4 Sip5ti4) is a nature reserve located near Yuen Long in Hong Kong. It is part of Deep Bay, an internationally significant wetland that is actually a shallow estuary, at the mouths of Sham Chun River, Shan Pui River (Yuen Long Creek) and Tin Shui Wai Nullah. Inner Deep Bay is listed as a Ramsar site under Ramsar Convention in 1995, and supports globally important numbers of wetland birds, which chiefly arrive in winter and during spring and autumn migrations. The education center and natural conservation area is 380 acres (1.5 km2) wide and its surrounding wetland has an area of 1500 acres (6 km2). It provides a conservation area for mammals, reptiles, insects, and over 350 species of birds.

The reserve is managed by the World Wide Fund for Nature Hong Kong since 1983; the Agriculture, Fisheries and Conservation Department has responsibilities for the Ramsar site as a whole. Deep Bay faces threats, including pollution, and rising mudflat levels that perhaps arise from intense urbanization, especially (in recent years) on the north, Shenzhen side of the bay.

In recent years, it housed over 55,000 migrating birds, including Saunders's gull (Chroicocephalus saundersi) and a quarter of the world's black-faced spoonbill (Platalea minor) population. It also has inter-tidal mangroves along with 24 traditionally operated shrimp ponds (called Gei Wai locally) to provide food for the birds. Mai Po Marshes receive 40,000 visitors annually.

While the area was taken out of the Frontier Closed Area on 15 February 2012, Mai Po Nature Reserve remains a restricted area under the Wild Animals Protection Ordinance (Chapter 170) in order to minimize disturbance to wildlife. Visitors need a 'Mai Po Marshes Entry Permit' to enter the Reserve which they can apply for by writing to the Agriculture, Fisheries & Conservation Department of Hong Kong Government. These permits are free and normally take about four weeks to be processed.

The marshes are also have rich insect biodiversity, being the place the endemic Mai Po bent winged firefly (Pteroptyx maipo Ballantyne) was discovered. Not only was the species new to science, but it was also the first time for the genus Pteroptyx has been recorded in China. To understand the seasonal population changes, distribution and habitat requirements of the species, WWF Hong Kong have been carrying out firefly surveys of the nature reserve. The surveys have also incorporated Citizen Science participation, and using this approach to further monitor the biodiversity, WWF have incorporated iNaturalist and the City Nature Challenge into activities at their Mai Po centre.

Mediterranean gull

The Mediterranean gull (Ichthyaetus melanocephalus) is a small gull. The scientific name is from Ancient Greek. The genus Ichthyaetus is from ikhthus, "fish", and aetos, "eagle", and the specific melanocephalus is from melas, "black", and -kephalos "-headed".This gull breeds almost entirely in the Western Palearctic, mainly in the south east, especially around the Black Sea, and in central Turkey. There are colonies elsewhere in southern Europe, and this species has undergone a dramatic range expansion in recent decades. As is the case with many gulls, it has traditionally been placed in the genus Larus.

Pacific gull

The Pacific gull (Larus pacificus) is a very large gull, native to the coasts of Australia. It is moderately common between Carnarvon in the west, and Sydney in the east, although it has become scarce in some parts of the south-east, as a result of competition from the kelp gull, which has "self-introduced" since the 1940s.

Much larger than the ubiquitous silver gull, and nowhere near as common, Pacific gulls are usually seen alone or in pairs, loafing around the shoreline, steadily patrolling high above the edge of the water, or (sometimes) zooming high on the breeze to drop a shellfish or sea urchin onto rocks.

Relict gull

The relict gull or Central Asian gull (Ichthyaetus relictus) 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.

Ring-billed gull

The ring-billed gull (Larus delawarensis) is a medium-sized gull. The genus name is from Latin Larus which appears to have referred to a gull or other large seabird. The specific delawarensis refers to the Delaware River.

Ross's gull

The Ross's gull (Rhodostethia rosea) is a small gull, the only species in its genus, although it has been suggested it should be moved to the genus Hydrocoloeus, which otherwise only includes the little gull.

This bird is named after the British explorer James Clark Ross. Its breeding grounds were first discovered in 1905 by Sergei Aleksandrovich Buturlin near village of Pokhodsk in North-Eastern Yakutia, while visiting the area as a judge. The genus name Rhodostethia is from Ancient Greek rhodon, "rose", and stethos, "breast". The specific rosea is Latin for "rose-coloured".

Slender-billed gull

The slender-billed gull (Chroicocephalus genei) is a mid-sized gull which breeds very locally around the Mediterranean and the north of the western Indian Ocean (e.g. Pakistan) on islands and coastal lagoons. Most of the population is somewhat migratory, wintering further south to north Africa and India, and a few birds have wandered to western Europe. A stray individual was reportedly seen on Antigua, April 24, 1976 (AOU, 2000).

The genus name Chroicocephalus is from Ancient Greek khroizo, "to colour", and kephale, "head". The specific genei commemorates Italian naturalist Giuseppe Gené.

Yellow-footed gull

The yellow-footed gull (Larus livens) is a large gull, closely related to the western gull and thought to be a subspecies until the 1960s. It is endemic to the Gulf of California.

Gulls (family: Laridae)
Genus
Larus
Ichthyaetus
Leucophaeus
Chroicocephalus
Saundersilarus
Hydrocoloeus
Rhodostethia
Rissa
Pagophila
Xema
Creagrus

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