The Chinese crested tern is the rarest member of the gull family (Laridae). Since it was first given a scientific name (Sterna bernsteini) in 1863, there had been only five confirmed sightings of this bird, and the last two-in Thailand in 1980 and in China's Yellow River delta in 1991-were not confirmed.

"They live mixed in with greater crested terns, and this makes them really difficult to pick out. But in our film they do show up very clearly," says Liang Chieh-te, who was commissioned to film greater crested terns by the Lienchiang County Government. The greater crested tern is around 45 centimeters long. Its most distinctive features are that it has a forked tail like a swallow, a crest of black feathers on its head rather like a Mohican haircut, and a yellow beak. The most visible difference of the Chinese crested tern from the greater crested tern is that its yellow beak has a black tip. Experts estimate that there may be less than 100 of the birds alive in the world today, and the species is listed as critically endangered in the world bird red data book.

Because there is so little information available about the Chinese crested tern, no-one can describe its distribution, appearance or behavior with any certainty. "From what we filmed, we can surmise that like the greater crested tern, Chinese crested terns' preferred habitats are harbors, estuaries and islands, and that they fly singly or in pairs and feed on fish and crustaceans," says Liang Chieh-te.

Nature photographer Lin Hsien-tang, who was a member of the camera team, says that the four pairs of adult birds discovered this time each hatched out a single chick. Unfortunately for the observers, the four breeding pairs' nesting sites were in amongst those of the greater crested terns, and under these conditions it was very difficult to distinguish how the appearance of their chicks might differ from that of greater crested tern chicks. Later, because strong winds and heavy seas made landing impossible, the camera team's plans were delayed. The next time they were able to land on the islet where the birds were filmed, the Chinese crested terns had already moved on, so the team missed the opportunity to observe them more closely.

From the 1960s to the 1980s, over 30 bird species regularly bred on uninhabited islands of the Matsu Archipelago, and at their peak their breeding populations numbered several tens of thousands. But later, because of excessive egg collecting by local inhabitants, and the widespread use of explosives by mainland Chinese fishing boats nearby, their numbers fell dramatically. In response, in 1999 the Lienchang County Government designated eight uninhabited islands-Paimiao, Chung Island, Tiehchien Island, Sanlien Islet and Chin Islet in Peikan Rural Township, Liuchuan Reef in Nankan Rural Township, Sheshan in Chukuang Rural Township and Shuangtsu Reef in Tungyin Rural Township-as gull refuges, and began recording the birds' natural history.

At present, the main summer-resident birds in the Matsu Archipelago include seven species: the bridled tern, the greater crested tern, the roseate tern, the black-naped tern, the black-tailed gull, the eastern reef heron and the northern white-rumped swift. Matsu is the only place in the whole of the Taiwan Area where the black-tailed gull breeds, and is at the northernmost limit of the greater crested tern's breeding range. The roseate tern is listed internationally as a critically endangered species.

Terns arrive in Matsu from the south in early May, and start looking for mates. They leave again in early September, having stayed in the Matsu area almost all summer.

The Lienchang County Government would like to make the gull refuges into an ecotourism attraction, but the birds' breeding is very easily disrupted by human disturbance. Implementing such plans in a way that properly meets the needs of both conservation and tourism will be a challenging task.