A common redshank is seen at Lhalu wetland in Lhasa, southwest China's Tibet Autonomous Region, June 27, 2019. Lhalu wetland national nature reserve is known as "the Lung of Lhasa". (Xinhua/Zhang Rufeng)

Wild ducks swim at the Lhalu wetland in Lhasa, southwest China's Tibet Autonomous Region, June 26, 2019. Lhalu wetland national nature reserve is known as "the Lung of Lhasa". (Xinhua/Zhang Rufeng)

A night heron is seen at Lhalu wetland in Lhasa, southwest China's Tibet Autonomous Region, June 26, 2019. Lhalu wetland national nature reserve is known as "the Lung of Lhasa". (Xinhua/Zhang Rufeng)

Common redshanks are seen at Lhalu wetland in Lhasa, southwest China's Tibet Autonomous Region, June 26, 2019. Lhalu wetland national nature reserve is known as "the Lung of Lhasa". (Xinhua/Zhang Rufeng)

A common redshank flies over Lhalu wetland in Lhasa, southwest China's Tibet Autonomous Region, June 26, 2019. Lhalu wetland national nature reserve is known as "the Lung of Lhasa". (Xinhua/Zhang Rufeng)

Photo taken on June 27, 2019 shows the view of the Lhalu wetland in Lhasa, southwest China's Tibet Autonomous Region. Lhalu wetland national nature reserve is known as "the Lung of Lhasa". (Xinhua/Zhang Rufeng)

A brown-headed gull flies over Lhalu wetland in Lhasa, southwest China's Tibet Autonomous Region, June 27, 2019. Lhalu wetland national nature reserve is known as "the Lung of Lhasa". (Xinhua/Zhang Rufeng)