The number of migratory birds living this winter in Poyang Lake, China's largest freshwater lake, increased by 27.4 percent compared to four years ago.

With an area of 3,583 square kilometers, Poyang Lake is an important habitat for migrant birds in winter. [Yangcheng Evening News]

The survey, conducted by the Poyang Lake National Nature Reserve Administration in February and March, showed the current number of waterfowl at Poyang Lake was about 409,077, up from 321,044 in the previous survey which was done in 2005.

The survey, released Wednesday, also showed that the number of birds such as white cranes, white stork and swans increased sharply.

Ji Weitao, director of the administration, said the increase was due to better protection measures such as around-the-clock patrolling to crack down on poaching since 2007. More high-tech devices, including telescopes and a global positioning system, were also used.

With an area of 3,583 square kilometers, Poyang Lake is an important habitat for migrant birds in winter. About 95 percent of the world's white cranes, half of the white-napped cranes and 60 percent of swan geese were believed to migrate there each year.