Black-headed gulls and cattle egrets are flocking to the Danjiangyuan wetlands, adding beauty and liveliness to Shangluo City, northwest China's Shaanxi Province.

The black-headed gull is a medium-sized waterfowl that flies to the north every March and April. The cattle egret is known for its symbiotic relationship with livestock as it feeds on parasites like ticks and flies on the back of cows and other large animals. During its breeding season, which usually begins in April, the birds will fly to the north and build their nest for future chicks.

The increasing number of migratory birds is a sign of good ecological condition in Danjiangyuan wetlands.

(Cover image: A cattle egret on the back of a cow. /VCG)

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