A bird perches on a branch at the Lhalu wetland in Lhasa, southwest China`s Tibet Autonomous Region, April 6, 2020. (Xinhua/Zhang Rufeng)

Birds are seen at the Lhalu wetland in Lhasa, southwest China`s Tibet Autonomous Region, April 6, 2020. (Xinhua/Zhang Rufeng)

Photo taken on April 6, 2020 shows a cormorant at the Lhalu wetland in Lhasa, southwest China`s Tibet Autonomous Region. (Xinhua/Zhang Rufeng)

Photo taken on April 6, 2020 shows a view of the Lhalu wetland in Lhasa, southwest China`s Tibet Autonomous Region. (Xinhua/Zhang Rufeng)

Photo taken on April 6, 2020 shows a view of the Lhalu wetland in Lhasa, southwest China`s Tibet Autonomous Region. (Xinhua/Zhang Rufeng)

Birds are seen at the Lhalu wetland in Lhasa, southwest China`s Tibet Autonomous Region, April 6, 2020. (Xinhua/Zhang Rufeng)

Birds are seen at the Lhalu wetland in Lhasa, southwest China`s Tibet Autonomous Region, April 6, 2020. (Xinhua/Zhang Rufeng)