Dozens of volunteers in the capital Beijing have launched a program for the protection of swifts, a common bird known for its aerial acrobatics and wild screams and the archetype for Nini, one of the mascots of Beijing Olympics.

Experts say swifts like to live under the roofs of Beijing's ancient city gate towers. Tens of thousands of swifts lived in the city in the 1950s and 1960s. But the reconstruction and renovation of the ancient buildings leave the birds a very limited number of places to live and reproduce.

In addition, the widespread use of pesticides harms the environment for the birds. Statistics show that there are fewer than 3,000 swifts in the capital at present.

Gao Wu, a bird protection expert, says citizens should undertake measures to protect swifts.

We should decrease or stop the use of pesticides and let the birds eat pests, so that the number of both birds and pests can be balanced. This can help foster a more harmonious coexistence between human beings and nature.

He calls on citizens to make artificial nests for the birds as swifts cannot make nests by themselves and often live in gaps in walls.

The expert says the nests can be placed under roofs or in porches.