Photo taken on July 17, 2013 shows a bird flying above the South China Sea. Over forty species of birds inhabit on Xisha Islands. (Xinhua/Lai Xiangdong)

Photo taken on July 18, 2013 shows a bird flying above the South China Sea. Over forty species of birds inhabit on Xisha Islands. (Xinhua/Lai Xiangdong)

Photo taken on July 18, 2013 shows a bird flying above the South China Sea. Over forty species of birds inhabit on Xisha Islands. (Xinhua/Lai Xiangdong)

Photo taken on July 17, 2013 shows a bird flying above the South China Sea. Over forty species of birds inhabit on Xisha Islands. (Xinhua/Lai Xiangdong)

Photo taken on July 18, 2013 shows a bird flying above the South China Sea. Over forty species of birds inhabit on Xisha Islands. (Xinhua/Lai Xiangdong)

Photo taken on July 18, 2013 shows two birds flying above the South China Sea. Over forty species of birds inhabit on Xisha Islands. (Xinhua/Lai Xiangdong)