Citizens in Dandong, Heilongjiang Province, are surprised to see flocks of long-disappeared mallards along the bank of the Yalu River.

The reappeared mallards are reported to be mostly belonging to the species of wild geese. They can be found in large numbers only in places with high-water quality, relatively safe living environment and a rich store of feed.

Cao Renjiang, director of Dandong Environmental Protection Bureau, told reporters that there were nearly 300,000 mallards in the mouths of the Yalu and Dayang rivers, including some red-nosed shelducks, a second-class State protected animals. In addition, there are also black-mouth gulls, the world's most valuable birds on the brink of extinction.

The Yalu River is now in the dry season when the river water was previously polluted most seriously, so birds were seldom seen at this time in the past, said Cao. Only in summer time when there was adequate rainfall and pollution was relatively light could people occasionally enjoy the sight of flocks of mallards in Dandong. This change demonstrates the initial results achieved in the control of pollution along the Yalu River over the past few years.

Since the nature reserve area centered around the mouths of the Yalu and Dayang Rivers was established with State approval given in February 1997, the number of mallards has been on the increase. After making observations on foot along the Yalu River for 10 days last year, a scientific investigation team finally affirmed that there were about 150,000 mallards here, but the figure has doubled this year. It is estimated that after the autumn breeding period, there will be a marvelous view of a million birds including the migratory ones.