A swan family is seen at the wetland park in Sanmenxia of central China’s Henan province, June 25, 2015. [Photo/Xinhua]

A swan family is seen at the wetland park in Sanmenxia of central China’s Henan province, June 12, 2015. [Photo/Xinhua]

A swan family is seen at the wetland park in Sanmenxia of central China’s Henan province, May 30, 2015. [Photo/Xinhua]

A swan family is seen on a lake in the Canglong lake of the wetland park in Sanmenxia of central China’s Henan province, June 25, 2015. [Photo/Xinhua]

A swan family is seen at the wetland park in Sanmenxia of central China’s Henan province, June 10, 2015.[Photo/Xinhua]