HOL XIL, June 8, 2016 (Xinhua) -- A flock of female Tibetan antelopes prepare to cross the Wubei Bridge of the Qinghai-Tibet Railway on the way to the breeding area Zhuonai Lake in Hol Xil Nature Reserve, northwest China's Qinghai Province, June 7, 2016. Tens of thousands of Tibetan antelopes are migrating to give birth near Zhuonai Lake, which provides an ideal environment for breeding. (Xinhua/Wu Gang)