Two black-headed gulls inside a state-level nature reserve by the estuary of Shuangtai River in Panjin City, Liaoning Province June 21, 2003. The black-headed gull is one of the bird species on the verge of global extinction. Scientists discovered that the estuary of Shuangtai River is a reproduction area for the bird in the early 1990s. Thanks to the joint efforts by the Panjin Municipal Government and the Panjin Black-headed Gulls Protection Association, the nature reserve has become the largest reproduction base for the bird in the world, with about 5,000 black-headed gulls dwelling in the reserve in 2003. (China.org.cn, 17thcongress.org.cn)