Swallows burrow holes for nests at building site in China's Henan

This photo taken on May 22, 2013 shows swallow nests on the subsoil at a building site in Xinzheng City, central China's Henan Province. Tens of thousands of swallows have burrowed holes here for nests in recent months. The builder has decided to postpone their construction work for a month to make sure the squabs born in those holes could grow up and be capable of flying. (Xinhua/Li Bo)