Thalasseus bernsteini 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Charadriiformes Laridae

Scientific Name: Thalasseus bernsteini
Species Authority: (Schlegel, 1863)
Common Name(s):
English Chinese Crested Tern, Chinese Crested-Tern
Sterna bernsteini Schlegel, 1863
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. Lynx Edicions BirdLife International.
Taxonomic Notes: Thalasseus bernsteini (del Hoyo and Collar 2014) was previously placed in the genus Sterna.

Identification information: 43 cm. Largish, slender, crested tern with black-tipped yellow bill. In flight, shows sharp contrast between pale grey upperwing and blackish outer primaries. Similar spp. Great Crested Tern S. bergii is larger, lacks prominent black tip to bill and has darker grey upperside.

Assessment Information [top]

Red List Category & Criteria: Critically Endangered C2a(i,ii); D ver 3.1
Year Published: 2015
Date Assessed: 2015-10-01
Assessor(s): BirdLife International
Reviewer(s): Symes, A.
Contributor(s): Chan, S., Hansbro, P., He, F., Kennerley, P., Liao, S., Liu, Y., Morning, F., Morris, P., Nisbet, I., Yang, L. & Robson, C.
Facilitator/Compiler(s): Benstead, P., Bird, J., Calvert, R., Crosby, M., Lascelles, B., Peet, N., Pilgrim, J., Symes, A., Taylor, J. & Ashpole, J
This poorly known species qualifies as Critically Endangered because it is estimated to have a tiny population, which is in decline owing to egg-collection, disturbance and the loss of coastal wetlands.

Previously published Red List assessments:
2013 Critically Endangered (CR)
2012 Critically Endangered (CR)
2010 Critically Endangered (CR)
2009 Critically Endangered (CR)
2008 Critically Endangered (CR)
2004 Critically Endangered (CR)
2000 Critically Endangered (CR)
1996 Critically Endangered (CR)
1994 Critically Endangered (CR)
1988 Threatened (T)

Geographic Range [top]

Range Description: The species is poorly-known, recorded breeding recently at only two sites on the eastern coast of China: Zhejiang and Fujian Provinces and, outside the breeding season, in Indonesia, Sarawak, Malaysia, Taiwan (China), Thailand and the Philippines (BirdLife International 2001). In June-July 1937, a total of 21 specimens were collected on islets off the coast of Shandong, where it was presumably breeding, indicating that it was locally not uncommon in the past; however, surveys conducted in June-July 2006 suggest that the regional breeding population has been extirpated from the coast of southern Shandong (Chen Shuihua et al. 2009, Liu Yang et al. 2009). Until the rediscovery of the breeding sites on Matsu Islands, Fujian and Jiushan Islands, Zhejiang, the only records were from China, in Hebei in 1978 and Shandong in 1991, with a possible record from peninsular Thailand in 1980.

In summer 2000 four adults and four chicks were found amongst a tern colony in the Matsu Archipelago off the east coast of mainland China (but administered by Taiwan). Breeding again took place in 2003, and in 2006 5-7 birds, including a pair of adults and a juvenile, were present (Candido 2006), with a total of 20, including three chicks, reported in 2008 (Hansbro in litt. 2008). In 2010 there were 15 adults and three nestlings at Matsu; there were six adults in 2011 and only four adults (with no successful breeding) in 2012 (S. Chan in litt. 2013). In 2015 the species again bred successfully on the Matsu Islands (Hurrell 2015).

A small group was also found breeding at Jiushan off the Zhejiang coast in 2004 (Kejia et al. 2004), but none bred there in 2005 or 2006; four pairs were recorded in 2007 but all eggs were collected by local people (Chen Shuihua 2007). Two pairs raised two young in 2008, but there was no breeding at Jiushan from 2009-2012 (S. Chan in litt. 2013). However, a small group, considered to be a former breeding group of the Jiushan birds, were found breeding at the Zhoushan Wuzhishan Archipelago nature reserve in 2008 (Shuihua Chen 2008, Chen Shuihua et al. 2010), with a maximum of 12 adults and three nestlings there in 2011 and eight adults and four nestlings in 2012 (S. Chan in litt. 2013). In 2015 the species successfully bred on the Wuzhishan Islands (Hurrell 2015). In 2013 Tiedun Dao islet in the Jiushan Islands was restored as a seabird colony (BirdLife International 2013). Vegetation was cleared, 300 tern decoys were placed on the island and solar-powered playback systems were used to play contact calls of Great and Chinese Crested Terns. By late July, 19 adult Chinese Crested Terns (the largest count since rediscovery) and 2,600 Great Crested Terns were present, and by September at least one juvenile Chinese Crested Tern had successfully fledged. In 2014 at least 43 adult Chinese Crested Terns were present on the island of Tiedun Dao for the breeding season, forming a minimum of 20 breeding pairs and fledging at least 13 chicks (Anon. 2014). In 2015 at least 25 pairs bred on Tiedun Dao and at least 16 chicks successfully fledged (Hurrell 2015).

Surveys of the coasts of Shandong and Zhejiang in 2003-2007 suggested that the breeding colonies on the Matsu and Jiushan Islands were the only ones still extant (Chen Shuishua et al. 2009). One to 11 birds (thought to be birds from the Matsu colony) are present from April to September at the Min Jiang estuary, Fujian. Since 2008, a small number of putative hybrid S. bernsteini x S. bergii have also been recorded and photographed at Min Jiang estuary (Chen Lin and He Fenqi 2011), with two recorded at the Matsu Archipelago in June 2011 (Wang Jianhua and He Fenqi in press). The species's movements and wintering grounds remain poorly understood, but heightened awareness in Taiwan (China) has resulted in several records of 1-2 birds using the Pachang River outside the breeding season since 1998 (P. Kennerley in litt. 2003), and more recently in 2004 at Chongming Dongtan National Nature Reserve, Shanghai (Kejia et al. 2004), and the Xisha Archipelago, indicating that it may winter around islands in the South China Sea. An individual was recorded on Pulau Lusaolate, north Seram, Indonesia in December 2010 (C. Robson in litt. 2010, Robson 2011). The species was again recorded at this location in November-December 2014, indicating that it may winter in eastern Indonesia (C. Robson in litt. 2015, S. Chan in litt. 2015).

It is thought that the species's known population can be divided into three small flocks: the Taiwan Straits flock, Zhoushan Archipelago flock and northern Chinese coast flock (Jiang Hangdong et al. 2010). In addition, a record of three birds at Rizhao, southern Shandong, in September 2011 adds support to the theory that another flock still exists along the coast of northern China (Qin Yupin and He Fenqi 2011), although these may be post-breeding stragglers from a known colony (Liu Yang in litt. 2012). There is also a very northern record from Tangu, Tianjin, in September 2008 (per Liu Yang in litt. 2012). The total current population is unknown, but is presumably tiny given the paucity of recent records.

Countries occurrence:
China; Indonesia; Malaysia; Philippines; Taiwan, Province of China; Thailand
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 9
Continuing decline in extent of occurrence (EOO): Unknown
Extreme fluctuations in extent of occurrence (EOO): No
Number of Locations: 2-5
Continuing 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: The number of breeding adults varies each year, ranging from 12 in 2012 to at least 43 in 2014. Given this the total number of mature individuals is likely to number fewer than 50, and perhaps most likely 30-49 (S. Chan in litt. 2013).

Trend Justification:  Repeat surveys at the two known breeding sites since 2003 have shown an overall decrease in the number of breeding pairs.

Current Population Trend: Decreasing
Additional data:
Number of mature individuals: 30-49 Continuing decline of mature individuals: Yes
Extreme fluctuations: No Population severely fragmented: No
No. of subpopulations: 1 Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No All individuals in one subpopulation: Yes
No. of individuals in largest subpopulation: 100

Habitat and Ecology [top]

Habitat and Ecology: Records indicate that it is exclusively coastal and pelagic in distribution. In China (including Taiwan), it has been found on offshore islets (breeding) and tidal mudflats. Breeding season late May to late August. Typically nests within large colonies of Great Crested Tern T. bergii (Gochfeld et al. 2015).

Systems: Terrestrial; Marine
Continuing decline in area, extent and/or quality of habitat: Yes
Generation Length (years): 11
Movement patterns: Full Migrant
Congregatory: Congregatory (and dispersive)

Threats [top]

Major Threat(s): Many coastal wetlands in its presumed breeding range in eastern China are affected by large-scale development projects and, in China, seabirds are exploited for food. The apparent extirpation of the population that formerly bred along the coast of southern Shandong is thought to be linked to the colonisation and development of its breeding islands since the 1950s (Liu Yang et al. 2009). Breeding failures in 1999, 2001, 2002, 2003 and 2005 at the Matsu tern colonies, and in 2007 in Zheijang Province may have been attributed to fishermen landing to collect shellfish and tern eggs (Candido 2006, Anon 2007a, Chen Shuishua et al. 2009) and this is probably by far the most serious immediate threat to the species. A study that monitored 45 nesting attempts by the species between 2004 and 2013 found that egg harvest accounted for 44% of nest failures (11 nests) whilst 48% (12 nests) were lost to typhoons (Chen et al. 2015). Many of the nest failures attributed to typhoons (58%) were re-nesting attempts after the first nesting attempt failed due to egg collecting, highlighting the synergistic effects that these two threats can have on the species (Chen et al. 2015). A typhoon hit Tiedun Dao during the 2015 breeding season but interventions to protect the colony (maintaining vegetation to act as a shelter and discouraging chicks from moving down to the shore) resulted in a casualty rate of less than 5% of the total colony (Hurrell 2015). Most of the failures occurred before 2008, since then measures have been put in place to protect colonies from egg collectors. The going rate for one seabird egg in Zhejiang more than doubled between 2005 and 2007, encouraging more people to enter the egg-collecting trade (Anon 2007a). An attempt to poach eggs from newly restored Tiedun Dao in the Jiushan Islands was prevented during the 2013 breeding season (Anon. 2014).

Putative S. bernsteini x S. bergii hybrids have been recorded and photographed at Min Jiang estuary since 2008 at least, thus hybridisation may be a significant threat to the population (Chen Lin and He Fenqi 2011). Oil spills are another potentially serious threat: a partly-oiled pair were present on the Min Jiang estuary in 2010 (P. Morris in litt. 2010). Rats are possibly present on Matsu and may predate nesting terns (Anon 2007b). Over-fishing and disturbance associated with fishing activities and tourism are additional potential threats (Chen Shuishua et al. 2009, Chan et al. 2010). Disturbance from dynamite fishing and other fishing activities in the likely wintering areas in eastern Indonesia also pose a threat (C. Robson in litt. 2015). The potential threat from the impact of pollution from domestic sewage and industrial effluent on the species's food supply is no longer considered likely (I. C. T. Nisbet in litt. 2010).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
The Matsu colony and surrounding islands were declared a national nature reserve in 2000 and eight islets have been declared 'preserved areas', with no-one allowed to land during the breeding season (Chang Shouhwa and Wang Dustin 2008). The Taiwanese Coast Guard patrols waters around the Matsu Islands and has recently begun seizing fishermen's nets if they are caught egg-collecting - this appears to be a major deterrent as there has been no recorded egg loss since (Anon 2007b). Reclamation at Min Jiang estuary was halted in 2006 and the site is now a provincial-level reserve (F. Morning in litt. 2008). The estuary was recently identified as of international importance for the species (Bai et al. 2015). In Thailand, it is nationally protected, and the locality where it was historically recorded is protected as the Laem Talumphuk Non-Hunting Area. A Special International Meeting of the Pacific Seabird Group was held in Lukang, Taiwan, in October 2007, at which the Chinese Crested Tern Working Group was formed and various conservation actions were discussed (Anon. 2007b).

An 18-month 'Critically Endangered Chinese Crested Tern' project ran from July 2008, it aimed to locate undiscovered breeding colonies and feeding areas in Fujian Province, to conduct education and awareness work at schools and local communities around key sites in northern Fujian, and raise awareness of the need for strengthened law enforcement and other actions among stakeholders in Fujian and Zhejiang Provinces (BirdLife International 2009). In April 2009, 20 participants attended the Chinese Crested Tern Conservation Meeting across the Taiwan Straits in Fuzhou City, Fujian (Cheung 2010). Amongst the coordinated conservation actions agreed were synchronised surveys to be carried out twice a month from June to August 2009 in the Matsu Islands and Min Jiang estuary to confirm the total number of individuals off the coast of Fujian, surveys for new breeding sites along the eastern coast of mainland China in the next few years, and investigation of migration routes and basic training for nature reserve staff and volunteers. A public seminar and photo exhibition were held in the public library of Fujian in the same month to raise awareness of the species and major threats. In October 2009, further awareness-raising activities were conducted in schools in coastal areas of Zhejiang and Fujian (Cheung 2010). Environmental education work is on-going (Hong Kong Bird Watching Society in litt. 2011). In November 2009, an international symposium on the Chinese Crested Tern was held in the Matsu Islands and was attended by almost 100 delegates (Chen Shuihua 2009, Gill 2010). A Species Action Plan was published in 2010 (Chan et al. 2010). A training workshop on Chinese Crested Terns was held in Zhejiang province, China in March 2013. The workshop focussed on habitat restoration at breeding colonies (Anon. 2013).

In 2013 Tiedun Dao islet in the Jiushan Islands was restored as a seabird colony (BirdLife International 2013). Vegetation was cleared, 300 tern decoys were placed on the island and solar-powered playback systems were used to play contact calls of Great and Chinese Crested Terns. By late July, 19 adult Chinese Crested Terns and 2,600 Great Crested Terns were present, and by September at least one juvenile Chinese Crested Tern had successfully fledged. During the 2014 and 2015 breeding seasons a warden was stationed on Tiedun Dao to monitor the species and deter egg collectors. At least 13 chicks fledged in 2014 (Anon. 2014) and at least 16 chicks fledged successfully in 2015 (Hurrell 2015). In 2015, 31 Chinese Crested Terns were fitted with leg bands in order to learn more about their ecology (Hurrell 2015). A series of meetings and workshops were organised to discuss the tern restoration work and a successful education campaign was implemented (Chan 2014). Plans are in place for the BirdLife Asia Division to work with Burung Indonesia to raise awareness of the species at potential wintering sites (Hurrell 2015).

Conservation Actions Proposed

A CMS International Single Species Action Plan (Chan et al. 2010) recommended a number of actions, including to: Conduct surveys at its former localities, both in the presumed breeding and non-breeding ranges, and at other potentially suitable breeding sites in China. Take immediate conservation measures to safeguard any sites found, especially nesting colonies. Upgrade the level of protection afforded to Min Jiang Estuary. Monitor the known breeding colonies, while taking care to avoid disturbance. Enforce a ban on landing on the breeding islands. Stop exploitation of the species, ensuring no eggs are taken - posting a warden at the Matsu Islands would be ideal; however this may not currently be possible for political reasons. Survey potential wintering areas and migration sites, including islands in the Seram Sea and Banda Sea (Robson 2011). Recent records of the species during the winter found it in areas with high concentrations of Greater Crested Terns Sterna bergii (C. Robson in litt. 2015) so these areas could be targeted in any future searches. Identify threats in the wintering areas (S. Chan in litt. 2015). Lobby to reduce the amount of pollution from industry. Strengthen the species's legal protection status. Conduct an education/awareness raising campaign to raise the profile of the species, including work in eastern Indonesia where the species is thought to winter (S. Chan in litt. 2015). Implementation of suggested actions is needed by all range countries. Study the species's breeding ecology, movements and genetic diversity (Liu Yang et al. 2009); a colour-ringing study was planned for 2015 (S. Chan in litt. 2015). Monitor the breeding colony on the Wuzhishan Archipelago.

Citation: BirdLife International. 2015. Thalasseus bernsteini. The IUCN Red List of Threatened Species 2015: e.T22694585A79181296. . Downloaded on 26 November 2015.
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