Chinese Crested Tern Thalasseus bernsteini Scientific name definitions

38–43 cm; 240–320 g; wingspan 94 cm. Large, slender tern with short crest and forked tail; recalls smaller and paler T. bergi. Breeding adult has complete black cap and shaggier crest. Non-breeding adult has black-tipped orange-yellow bill, white forehead, forecrown and lores, and has black mask from eye to nape. In flight, blackish primaries contrast with white underwing. Rump, tail and uppertail-coverts concolorous with very pale grey mantle and upperwing. Juvenile like non-breeding adult but has two brownish inner bars on upperwing. Similar to T. bengalensis, but bill stouter , with more pronounced gonydeal angle, orange-yellow with broad black tip; back paler grey.

• Great x Chinese Crested Tern (hybrid) Thalasseus bergii x bernsteini

Poorly known. Only recent breeding records at three sites on E China coast, in Jiushan Is and Zhoushan Wuzhishan Is (Zhejiang) and Matsu Is (off Fujian) (1 BirdLife International (2013). IUCN Red List for birds. URL: http://www.birdlife.org (download Aug 2013). Close , 2 Chen Shuihua, Fan Zhongyong, Chen Cangsong, Lu Yiwei and Wang Zhongde (2010). A new breeding site of the Critically Endangered Chinese Crested Tern Sterna bernsteini in the Wuzhishan Archipelago, eastern China. Forktail 26: 132–134. Close ); formerly bred off Shandong, but probably extirpated (3 Liu Yang, Guo Dong-Sheng, Qiao Yi-Lun, Zhang Er and Cai Bofeng (2009). Regional extirpation of the Critically Endangered Chinese Crested Tern (Thalasseus bernsteini) from the Shandong Coast, China? Waterbirds 32(4): 597–599. Close ). Non-breeding records in SE China, Thailand, Sarawak, Philippines and N & C Moluccas (Halmahera, Seram).

Exclusively coastal and pelagic.

Appears to migrate to tropics, where recorded from E China (Fujian, Guangdong), Philippines, NW Borneo (Sarawak), S Thailand and Halmahera. Recorded also in Seram I, Moluccas, Indonesia (Dec 2010, Jan 2016).

During breeding season adults forage within c. 5 km of the breeding islets and feed chicks mainly with small and/or young shoaling fishes (4 Chen, S.H., Fan, Z.Y., Chen, C.S. and Lu, Y.W. (2011). The breeding biology of Chinese Crested Terns in mixed species colonies in eastern China. Bird Conservation International. 21: 266–273. Close ). No other information.

Poorly documented. Calls include a high-pitched rolling “keerrick” and lower-pitched grating calls.

On Jiushan and Wuzhishan archipelagos, Zhejiang province, NE China, six nests confirmed during 2004–2009; breeding season, late May–late Aug; nests generally within large colonies of Thalasseus bergii on small, uninhabited islets devoid of tall vegetation; in four monitored nests clutch always one egg; incubation period 22–28 days; fledging period 31–35 days; chicks subsequently join crèche of T. bergii; 100% breeding success (4 Chen, S.H., Fan, Z.Y., Chen, C.S. and Lu, Y.W. (2011). The breeding biology of Chinese Crested Terns in mixed species colonies in eastern China. Bird Conservation International. 21: 266–273. Close ).

CRITICALLY ENDANGERED. Poorly known and total population apparently fewer than 100 individuals. For more than 100 years known only from a few specimens collected prior to 1937, and a few, mostly unconfirmed, sightings in China, Thailand and Indonesia. However, in summer 2000 eight adults and four chicks were found within a T. bergii colony on Matsu Is, Taiwan (5 Liang, C. T., Chang, S. H. and Fang, W. H. (2000). Little known Oriental bird: discovery of a breeding colony of Chinese Crested Tern. Oriental Bird Club Bulletin. 32: 18. Close ), and subsequently the species was found also breeding in very small numbers on Jiushan Is and Wuzhishan Is, Zhejiang province, China, in 2004 and 2009, respectively (6 Chen, S.H., Fan, Z.Y., Chen, C.S. and Lu, Y.W. (2010). A new breeding site of the Critically Endangered Chinese Crested Tern Sterna bernsteini in the Wuzhishan Archipelago, eastern China. Forktail. 26: 132–133. Close ). Other recent records include three birds seen in Sept 2011 in Shandong province, N China (7 Qin, Y. and He, F. (2011). Latest evidence of the existence of the northern flock of the Chinese Crested Tern (Sterna bernsteini). Chinese Birds. 2(4): 206–207. Close ). A restoration project has been attempted on the Jiushan Is since 2013. Here, in 2014 at least 20 breeding pairs produced 13 young to fledging External link , while in 2015 at least 16 young were raised (8 Ławicki, Ł., and A. B. van den Berg (2015). WP reports. Dutch Birding 37(5):340–353. Close ). Two new breeding sites were found in 2016: two pairs nested on an uninhabited island off SW coast of Korea and three pairs bred on Jishan-yu, Penghu Is, in Taiwan Strait (9 He, Fen-Qi and Jiang, Hang-Dong. (2017). New records of Critically Endangered Chinese Crested Tern Thalasseus bernsteini in 213816 indicate ongoing breeding success. BirdingASIA. 27: 86–87. Close ). The Korean birds were the first to be found nesting outside coastal China and were in a Larus crassirostris colony, not among other terns. Habitat degradation, egg poaching, disturbance, overfishing and typhoons are major threats (10 Chen, S., Chang, S.H., Liu, Y., Chan, S., Fan, Z., Chen, C., Yen, C. and Guo, D. (2009). A small population and severe threats: status of the Critically Endangered Chinese crested tern Sterna bernsteini. Oryx. 43(2): 209-212. Close ). Hybridization with T. bergii is perhaps also a problem (11 Chen, L. and He, F. (2009). Are they hybrids of Sterna bergii x Sterna bernsteini? Chinese Birds. 2(3):152-156. Close ).