Over a thousand migrating swans arrived at Xuejiaying Reservoir in the north of Shanxi Province. They stay for a month each year, then fly on to warmer areas in the south. Thousands of other migrating birds are resting here. Around 800 swans have also arrived at Shengtian Lake in the south of Shanxi Province. The lake is in a national wetland reserve along the Yellow River. Officials say about 200 swans have been arriving each day. Protection measures are in place to keep them safe.