The Chinese Crested Tern (Thalasseus bernsteini) is one of the most endangered seabird species, whose breeding range is restricted to the East China Sea and the Yellow Sea.
Chinese Crested Tern was first discovered in Indonesia in 1861. After that, only a limited number of Chinese Crested Tern specimens were collected in Malaysia, the Philippines, Thailand and China (Shandong and Fujian Province). The last confirmed record was in the Moguan Island and Jiaozhou Bay in Qingdao, Shandong Province in 1937. The species then seemed to disappear for such a long time that many ornithologists believed it was indeed extinct. Sixty-three years later, in 2000, it was rediscovered in the Mazu islands. Due to its rarity and limited knowledge of its behavior, it was given the name, ‘the Bird of Mystery’.
The population of Chinese Crested Tern showed a big fluctuation from year to year due to the unstable condition of the breeding sites, mostly caused by human activities (such as egg poaching, shellfish collecting by fishermen, island exploitation and environmental pollution). In order to protect this critically endangered seabird, research team of Zhejiang Museum of Natural History, leading by Dr. Shuihua Chen and cooperating with Dr. Daniel Roby from the Oregon State University, initiated the tern restoration project using social attraction technique in Jiushan Islands National Nature Reserve, Xiangshan County, Ningbo City in 2013. The technique is based on a typical behavior of terns which usually breed in colony and their nesting behaviors can be easily influenced by peers choice. By placing decoys and using sound playback, the team intended to attract the passing terns to land and breed at chosen sites. This technique was invented in 1970s by American Ornithologist Dr. Steve Kress, has been used in at least 171 different seabird restoration projects conducted in 16 countries/regions in an attempt to conserve and restore population of at least 64 seabird species.
Tiedun Islet (in Jiushan Archipelago, Ningbo, Zhejiang Provicne) was chosen by research team as the tern restoration site in 2013. Nesting ground was well-designed: 400 tern decoys and two solar-powered playback system were deployed before breeding season. The technique quickly paid off: at least 3300 Greater Crested Terns and 19 Chinese Crested Terns were attracted to the site in middle July, and nearly half of them began to breed. Eventually more than 600 Greater Crested Tern chicks and at least 1 Chinese Crested Tern chick successfully fledged in October. The project achieved a big success in the first year. Since 2015, research team conducted the social attraction programs on Jiushan Archipelago and Wuzhishan Archipelago simultaneously and has made continuous success. As a result, the population of Chinese Crested Tern has gradually increased by years. By the end of the breeding season in 2018, the number of Chinese Crested Tern has increased from less than 50 before 2010 to more than 100 individuals.
The major advantage of the application of social attraction technique is to establish a strictly monitored and protected breeding population and to ensure its breeding success. Besides, this technique allows monitors observing terns closely without disturbing them, which is helpful to detect the potential threats to the breeding colony. Higher reproduction rate is expected by eliminating these threats. Moreover, new technique had drowned much public attention and greatly enhanced public conservation awareness of this critically endangered species. In the future, with the populations of both Greater Crested Terns and Chinese Crested Terns apparently increasing, more new breeding colonies could be created using social attraction. By persisting in this approach, a well-protected, closely monitored, and extensive conservation network of tern breeding islands could be developed in the East China Sea, and potentially in the Yellow Sea as well, where the Chinese crested tern was originally described.
This project is the first attempt in China that attracts seabirds to nest on a site chosen by human. It promises to provide much valuable experience for the conservation of breeding seabirds and facilitate seabird restoration throughout China. This success would also provide a new way for wildlife conservation and nature reserve management in China.
The research and results were published online at biological conservation, and is open access and available at: https://doi.org/10.1016/j.biocon.2020.108694.
Prepared by research team from Zhejiang Museum of Natural History
由于受到人为捡蛋、渔民采贝、栖息地丧失、环境污染等因素的影响，中华凤头燕鸥的种群数量波动很大，繁殖地点也不固定。为了保护这一濒临灭绝的鸟类，浙江自然博物院的研究团队在陈水华博士带领下，从2013年开始，与美国俄勒冈州立大学Daniel Roby教授合作，首先在宁波市象山县韭山列岛国家级自然保护区开展人工招引鸟类试验。即采用社群吸引技术，利用燕鸥集群繁殖的习性，通过放置燕鸥假鸟模型、播放燕鸥鸣声，吸引中华凤头燕鸥和大凤头燕鸥到特定的栖息地繁殖。这项技术自20世纪70年代由美国鸟类学家Steve Kress博士发明以来，被广泛应用于海鸟恢复和保护项目，目前至少在16个国家和地区171个不同海鸟恢复项目中应用了这项技术，至少64种海鸟种群得以保护和恢复。
该项研究和实验成果近日在线发表于国际保护生物学主流杂志 Biological Conservation，论文链接：https://doi.org/10.1016/j.biocon.2020.108694。