Zhang Bin, a wildlife photographer who has been working as a research volunteer at the Chongming Dongtan National Nature Reserve since 2002, recalled how people used to hunt the migratory birds on the island, trapping them with nets along the coast and killing them for food.

However, the construction of protected areas such as the nature reserve and the implementation of enforcement measures has greatly improved the environment for migratory birds, he added. In addition, officials have been cooperating with wildlife experts for the past six years to determine how the natural conditions can be improved.

But the lack of official regulations regarding the conduct of birdwatchers and photographers elsewhere has at times created problems.

"In order to get a nicer photo, some photographers throw stones or sticks at the birds to get them to fly. Others even manipulate the habitats by clearing the surroundings. This destroys the birds' homes and some even get eaten by predators because of this," said Zhang.

"These actions can sometimes cause devastating consequences to nature and the ecological system."