Photo taken on April 29, 2020 shows a yellow-billed chough at Mount Qomolangma National Nature Reserve in southwest China's Tibet Autonomous Region. Mount Qomolangma National Nature Reserve was set up in 1988. Covering an area of more than 33,800 square km, it is home to one of the world's most vulnerable ecosystems. (Xinhua/Jigme Dorje)
