Searching for a song

When Chen Liang was offered a chance to trek through a beautiful stretch of forest to listen to the song of the endangered western black-crested gibbon, he jumped at the chance. Little did he know the trek would be a test for even the most hardened outdoorsman.

It was an offer too good to refuse.

"Participants will trek through the key habitats of western black-crested gibbons on the Ailao Mountains, or Ailaoshan, in Yunnan province," the invitation read. "Listen to their singing in the morning, observe the rich fauna and flora in the day and stargaze at night."