A small population and severe threats: status of the Critically Endangered Chinese crested tern Sterna bernsteini.

The Critically Endangered Chinese crested tern Sterna bernsteini is a poorly known species. From June 2003 to August 2007 we therefore surveyed the Zhejiang and Shandong coasts of eastern China for breeding colonies and to document any threats. Our results indicated that (1) the colonies at Matzu and Jiushan are the only two in the species' potential breeding range, (2) the total population is no more than 50, (3) numbers in the two extant breeding colonies fluctuate annually, and (4) threats to the breeding populations include habitat degradation, egg poaching, disturbance, overfishing and typhoons. Egg poaching is the greatest threat to the Chinese crested tern population and other breeding seabird populations along the coast of China. We make recommendations for the conservation of this species.