Situated in northern Jiangxi,Poyang Lake,the largest fresh water lake in China, lies to the south of the middle and lower reaches of the Changjiang River. It stretches 170 km from north to south (28° 25' - 29°45' N ), and 74 km at its broadest east to west (115 –116°44' E ), covering a total area of about 3,841 square kilometres (when water depth at Hukou where the lake joins the Changjiang River is 21 meters). Its coast line is 1,800 km. The lake has been well known as "a land of abundance" and is reputed as a "bright pearl" in the basin of the Changjiang River with its rich aquatic resources and flourishing crops in surrounding fertile lands. The lake area enjoys a subtropical warm and wet climate with suffucuent sunshine, ample precipitation and long frost-free period. The average annual temperature varies from 16.7 to 17.7 degrees C and the average yearly is 1,400 to 1,900 mm. From April to June during the flood season, its surface area is considerably expanded forming an endless rippling blue expanse. In the dry season of winter and spring, the water recedes and seasonal small lakes and large marshes appear all over the lake area. According to preliminary survey, there exist in the lake 25 families of phytoplankton totalling almost 100 species, the dominant being green algae,37 families of aquatic vascular plant with 98 species, the dominant being sedge, Potamogeton malaianus and Vallisneria spiralis; 65 species of mollusca, the dominant being snail and mussel; 21 families of fish with 122 species, the dominant being Cyprinidae. In addition, there is a good supply of silver fish, a famous product of the area. Spreading on the grassland along the banks are 74 species of 25 families of meadow and helophyte plants, the dominant being Gramineae, Cyperaceae, Polygonaceae and Compositae. Such abundant natural resources provide a welcoming habitat for birds, attracting tens of thousands of migratory birds to spend their winter there, thus turning the Poyang Lake into one of the world's most famous migratory birds sanctuaries. In June, 1983, the People's Government of Jiangxi Province established the Migratory Birds Reserve in the western part of Poyang Lake where most of the migratory birds flock there for winter, and set up corresponding administrations. This Reserve, with Wucheng in Yongxiu County as its center, embraces nine seasonal lakes and marshes including: Dahuci, Banghu, Zhonghuci, Shahu, with a total area of 22,400 ha. There dwell in the Reserve 150 species of birds among which many are rare ones listed for global protection. In February 1984, 840 white cranes were observed, the largest flock of white cranes ever found in the world. This number has increased considerably in recent years. On 12th of January 1985, a crane inspection de legation from the International Crane Fund witnessed over 1,350 white crane. In the winter of 1985 the number increased to about 1,500. In addition, 20 species of rare birds such as white naped crane, hooded crane, common crane, white stork, black stork, spoonbill, whistling swan, mandarin duck, great bustard and pelican also frequent the area. The Poyang Lake Migratory Birds Reserve has been visited by specialists and scholars of the International Crane Fund, the Interna-tional Union for Protection of Nature and Natural Resources, the Hong Kong Branch of WWF, Japan, Sweden, Spain and other countries, and has been highly spoken of by them as a "paradise" and "gold reserve newly discovered". The large flock of cranes stretching over a few kilometres has been acclaimed China's "Second Great Wall". The establishment of the Migratory Birds Reserve offers favourable conditions for both the protection of migratory birds and scientific research on wetland as well as public awareness drives for loving and protecting birds". The area will, as a result, gradually become a center of crane research and wetland education in the southern part of China. It will also become a scenic spot for both Chinese and foreign tourists to view the migratory birds.