An eye on the sky

Equipped with a set of binoculars, a flashlight and a notebook, Zang Erjun set out into the wetlands at the Caohai National Nature Reserve in southwest China's Guizhou Province, shrouded in morning mist. Observing through his binoculars, he saw a flock of large, whitish-grey cranes standing in the water. "In half an hour, they will fly into the mountains," he said.

Patrolling the wetland, monitoring bird species, preparing feeds and warding off occasional bird hunters - this has been the daily life of Zang, the 59-year-old ranger at the reserve, for the past 18 years.

Located in the mountainous areas in Weining autonomous county of Yi, Hui and Miao ethnic groups, the reserve is the wintering area for black-necked cranes, classified as a vulnerable species by the International Union for Conservation of Nature. The population of black-necked cranes has been in decline due to the loss and degradation of wetlands.

In Caohai, however, their numbers are growing thanks to the implementation of an integrated program of conservation and development. Zang said he recorded just over 300 black-necked cranes in 1997, the year when he started his job at the reserve. In 2014, the number has risen to around 1,000.