As the cold sets in in northern China, thousands of migratory birds have moved to their winter resort. Many cranes and swans have returned to the Poyang Lake in central China's Jiangxi Province. But this winter their living conditions have worsened.

Exhausted by the long journey, these birds can finally rest their wings in China's largest freshwater lake.

But it's not only mother nature who has been preparing for their arrival.

30 white cranes and 16 swans.

It's 7 a.m., and Wu Xudong has started working with his team at Poyang Lake Bird Protection Area to prepare for the migratory birds arrival.

Having worked at the lake for 16 years, he is very familiar with the local eco-system. This year, he is mostly worried about the birds.

Droughts have hit the area badly, shrinking the lake to less than half its size. Wu and his team are watching closely for changes in the water level.

Wu said, "We used to dry out the lake a bit so the birds could feed on the mudflat. But this winter, there is no need, or else the lake would disappear."

The Bird Protection Area is home to many rare birds, like the white crane and swan goose. Their population has been growing due to suitable environments. But as the water level decreases, the area is forced to make a back-up plan for feeding.

Wu said, "We'll pump water from surrounding rivers into the lake. Meanwhile, we'll put fish into the lake for the birds to feed on, and we may use planes to help on that."

Birds protectors now have to walk 70-80 kilometers everyday to records the birds' conditions as well as the water level. It's hard work, but the pay off is seen in the number of birds that come back each year.

(CNTV.cn January 9, 2012)