Black-necked cranes search for food at a farm in Dagze District of Lhasa, southwest China`s Tibet Autonomous Region, on Jan. 5, 2020. With its favorable environment, Lhunzhub County and Dagze District have attracted migratory black-necked cranes in winter. (Xinhua/Zhang Rufeng)

Black-necked cranes fly over a reservoir in Lhunzhub County, Lhasa, southwest China`s Tibet Autonomous Region, on Jan. 5, 2020. With its favorable environment, Lhunzhub County and Dagze District have attracted migratory black-necked cranes in winter. (Xinhua/Zhang Rufeng)

Black-necked cranes fly at a natural reserve in Lhunzhub County, Lhasa, southwest China`s Tibet Autonomous Region, on Jan. 5, 2020. With its favorable environment, Lhunzhub County and Dagze District have attracted migratory black-necked cranes in winter. (Xinhua/Zhang Rufeng)

Black-necked cranes fly at a natural reserve in Lhunzhub County, Lhasa, southwest China`s Tibet Autonomous Region, on Jan. 5, 2020. With its favorable environment, Lhunzhub County and Dagze District have attracted migratory black-necked cranes in winter. (Xinhua/Zhang Rufeng)

Black-necked cranes fly at a natural reserve in Lhunzhub County, Lhasa, southwest China`s Tibet Autonomous Region, on Jan. 5, 2020. With its favorable environment, Lhunzhub County and Dagze District have attracted migratory black-necked cranes in winter. (Xinhua/Zhang Rufeng)

Black-necked cranes are seen at a reservoir in Lhunzhub County, Lhasa, southwest China`s Tibet Autonomous Region, on Jan. 5, 2020. With its favorable environment, Lhunzhub County and Dagze District have attracted migratory black-necked cranes in winter. (Xinhua/Zhang Rufeng)

Black-necked cranes are seen at a reservoir in Lhunzhub County, Lhasa, southwest China`s Tibet Autonomous Region, on Jan. 5, 2020. With its favorable environment, Lhunzhub County and Dagze District have attracted migratory black-necked cranes in winter. (Xinhua/Zhang Rufeng)

Black-necked cranes fly at a natural reserve in Lhunzhub County, Lhasa, southwest China`s Tibet Autonomous Region, on Jan. 5, 2020. With its favorable environment, Lhunzhub County and Dagze District have attracted migratory black-necked cranes in winter. (Xinhua/Zhang Rufeng)

Black-necked cranes fly at a natural reserve in Lhunzhub County, Lhasa, southwest China`s Tibet Autonomous Region, on Jan. 5, 2020. With its favorable environment, Lhunzhub County and Dagze District have attracted migratory black-necked cranes in winter. (Xinhua/Zhang Rufeng)

Black-necked cranes fly over a reservoir in Lhunzhub County, Lhasa, southwest China`s Tibet Autonomous Region, on Jan. 5, 2020. With its favorable environment, Lhunzhub County and Dagze District have attracted migratory black-necked cranes in winter. (Xinhua/Zhang Rufeng)

Black-necked cranes are seen at a reservoir in Lhunzhub County, Lhasa, southwest China`s Tibet Autonomous Region, on Jan. 5, 2020. With its favorable environment, Lhunzhub County and Dagze District have attracted migratory black-necked cranes in winter. (Xinhua/Zhang Rufeng)

Black-necked cranes fly at a natural reserve in Lhunzhub County, Lhasa, southwest China`s Tibet Autonomous Region, on Jan. 5, 2020. With its favorable environment, Lhunzhub County and Dagze District have attracted migratory black-necked cranes in winter. (Xinhua/Zhang Rufeng)

Black-necked cranes are seen at a reservoir in Lhunzhub County, Lhasa, southwest China`s Tibet Autonomous Region, on Jan. 5, 2020. With its favorable environment, Lhunzhub County and Dagze District have attracted migratory black-necked cranes in winter. (Xinhua/Zhang Rufeng)

Black-necked cranes are seen at a reservoir in Lhunzhub County, Lhasa, southwest China`s Tibet Autonomous Region, on Jan. 5, 2020. With its favorable environment, Lhunzhub County and Dagze District have attracted migratory black-necked cranes in winter. (Xinhua/Zhang Rufeng)