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Saundersilarus saundersi 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Charadriiformes Laridae

Scientific Name: Saundersilarus saundersi
Species Authority: (Swinhoe, 1871)
Common Name(s):
English Saunders's Gull, Chinese Black-headed Gull
Synonym(s):
Larus saundersi (Swinhoe, 1871)
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.
Taxonomic Notes: Saundersilarus saundersi (del Hoyo and Collar 2014) was previously placed in the genus Larus.
Identification information: 33 cm. Diminutive gull with shortish, black bill. Breeding adults have black hood extending to nape and broad, broken white eye-ring. Non-breeders have white tips and small, black subterminal markings on outer primaries, small black tips to inner primaries, narrow, broken, dark secondary band and narrow black tail-band. Similar spp. Black-headed Gull L. ridibundus is larger, less compact with longer bill and white leading edge to wing.

Assessment Information [top]

Red List Category & Criteria: Vulnerable A3cde+4cde ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Hark-Jin, K., Holt, P. & Liu, Y.
Facilitator/Compiler(s): Anderson, O., Benstead, P., Bird, J., Chan, S., Khwaja, N., Peet, N., Pilgrim, J. & Taylor, J.
Justification:
This species's moderately small population is thought to be in decline, and this is likely to become rapid over the next three generations (18 years) as a result of land reclamation on tidal flats and disturbance at colonies, resulting in its listing as Vulnerable.

Previously published Red List assessments:

Geographic Range [top]

Range Description:Saundersilarus saundersi breeds in eastern mainland China, and sporadically at sites on the south-west coast of South Korea (BirdLife International 2001). The most important breeding grounds are Yancheng National Nature Reserve and Shuangtai Hekou National Nature Reserve in China. A count of 1,317 birds was made at Shuangtai Hekou, Liaoning in October 2001 (Robson 2002), with 8,671 adults recorded and 399 banded in 2007 (Jiang Hongxing 2007). At the Yellow River Delta of Shandong, 801 adults were recorded and 27 juveniles banded, while in Yancheng of Jiangsu, 575 adults were recorded in 2007 (Jiang 2007). Non-breeding birds occur in North Korea, where it may also breed. It winters in eastern and southern China (9,625 individuals), from Jiangsu southwards, Hong Kong (China) (35 individuals), Macau (China), Taiwan (China) (700 individuals), along the western and southern coast of South Korea (2,000 individuals), in south-western Japan (2,000 individuals) and in Vietnam (10 individuals) (Cao et al. 2008). The coast of Dandong is an important stopover site on the flyway of Panjing-Japan, with 232 adults sighted in April 2008, 75% of which were sub-adults in their first winter (Bai Quing-Quan 2008). The key wintering grounds are Bohai Bay, where 864 birds were counted in 2005/2006 (Liu Yang et al. 2007) and Wenzhou-Yueqing bays, Guangdong and Guangxi in China and Suncheon-Kwangyang bays, with c.750 individuals recorded at Kum River estuary in January 2004 (Kim Hark-Jin in litt. 2004), in South Korea. The global population is estimated to be 7,100-9,600 birds although recent figures point to a minimum of 14,400 birds, mostly likely due to increased survey effort rather than any real increase in the population (Cao et al. 2008). However, it is likely that the population is continuing to decline, given the significant threats to habitat and high human disturbance levels occurring across the species's range (Jiang et al. 2010).

Countries occurrence:
Native:
China; Hong Kong; Japan; Korea, Democratic People's Republic of; Korea, Republic of; Macao; Russian Federation; Taiwan, Province of China; Viet Nam
Additional data:
Continuing decline in area of occupancy (AOO):Yes
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:531000
Continuing decline in extent of occurrence (EOO):YesExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:11-100Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:No
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:A population estimate of 14,400 mature individuals has been derived from analysis of records and surveys by BirdLife International (2011). This is roughly equivalent to 21,000-22,000 individuals in total.

Trend Justification:  The species's population is presumed to be declining in line with the rate of habitat loss owing to land reclamation, which is anticipated to increase in the near future. Studies at specific sites have shown declines, for example a drop from over 900 individuals to 575 in the last 15 years at Yancheng National Nature Reserve (Jiang et al. 2010).

Current Population Trend:Decreasing
Additional data:
Number of mature individuals:14400Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:No
No. of subpopulations:2-100Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:It nests on the ground and is restricted to common seepweed Suaeda glauca saltmarsh habitats. Wintering birds are found on estuarine tidal flats with regular movements between different sites dependent on weather and food supply.

Systems:Terrestrial; Marine
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):11.5
Movement patterns:Full Migrant
Congregatory:Congregatory (and dispersive)

Threats [top]

Major Threat(s): The key threat is reclamation of tidal flats and saltmarshes, particularly in China, Taiwan, South Korea and Japan. From 1990-1995, many former breeding sites at Yancheng were lost through reclamation and construction. Common seepweed habitat, in which the species nests, decreased in areas by 79.1% (27,358 ha) over 15 years predominantly as a result of conversion to aquaculture ponds (Jiang et al. 2010). In 2011, many chicks and eggs at a breeding colony in Panjin were lost to rising water levels associated with land conversion to aquaculture ponds, which is a potential future threat to other colonies (Liu Yang in litt. 2012). The introduction of smooth cordgrass Spartina alterniflora in 1982 has also caused considerable habitat degradation by replacing common seepweed habitats and increasing in area by 322% (11,057 ha) between 1999 and 2007 (Jiang et al. 2010). The other two breeding sites in China, Shuangtai Hekou and the Yellow River delta, are major oilfields and birds are under increasing threats from pollution and human activities. Reclamation developments associated with the Tianjin New Coastal District project (started in 2006) had seriously impacted an important wintering area by autumn 2011, resulting in a substantial loss of inter-tidal mudflats in Tianjin municipality (P. Holt in litt. 2012). Disturbance of nest-sites is a problem, particularly through the collection of lugworms on tidal flats in China, and by photographers in South Korea. The disturbance of adults results in increased predation of eggs and chicks. In China, eggs are sometimes collected by fishers. Unfavourable weather conditions threaten birds and nests at Yancheng.

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
CMS Appendix I. The key nesting sites in China are all nature reserves. Wintering sites at Manko (Japan), Mai Po (Hong Kong), and Xuan Thuy (Vietnam) are all protected areas. The species is classed as Vulnerable in China and therefore receives full legal protection.

Conservation Actions Proposed
Conduct surveys in North Korea for potential breeding sites. Expand the Yellow River Delta Nature Reserve (China), to include additional nest-sites. Establish protected areas at the wintering sites of Wenzhou-Yueqing bays (China), Tutu estuary, Hanpao and Aoku (Taiwan), Suncheon-Kwangyang bays (South Korea), Daijyu-garami, Hakata Bay and Sone (Japan). Provide management plans for coastal wetlands to promote their conservation and prevent the expansion of smooth cordgrass through active management measures (Jiang et al. 2010). Ensure full legal protection for this species.


Citation: BirdLife International. 2016. Saundersilarus saundersi. The IUCN Red List of Threatened Species 2016: e.T22694436A93453163. . Downloaded on 28 May 2017.
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