Birds fly over the Yuehai national wetland park of Yinchuan, capital of northwest China's Ningxia Hui Autonomous Region, April 21, 2011. As the weather become warmer, some 7,000 birds like herns, egrets and gulls were engaged in breeding here. There are some 200 natural lakes scattered in the wetlands surrounding Yinchuan, which form an ideal environment for those birds to live, rest and breed. [Wang Peng/Xinhua]