An aerial drone photo taken on June 15, 2024 shows a view of the Tianshui River in the Qiangtang National Nature Reserve in southwest China's Xizang Autonomous Region. Tianshui River is an important migratory passage for pregnant Tibetan antelopes in the Qiangtang National Nature Reserve. (Xinhua/Jigme Dorje)

An aerial drone photo taken on June 14, 2024 shows a view of the Tianshui River in the Qiangtang National Nature Reserve in southwest China's Xizang Autonomous Region. Tianshui River is an important migratory passage for pregnant Tibetan antelopes in the Qiangtang National Nature Reserve. (Xinhua/Purbu Tsering)

An aerial drone photo taken on June 15, 2024 shows a view of the Tianshui River in the Qiangtang National Nature Reserve in southwest China's Xizang Autonomous Region. Tianshui River is an important migratory passage for pregnant Tibetan antelopes in the Qiangtang National Nature Reserve. (Xinhua/Jigme Dorje)

An aerial drone photo taken on June 14, 2024 shows a view of the Tianshui River in the Qiangtang National Nature Reserve in southwest China's Xizang Autonomous Region. Tianshui River is an important migratory passage for pregnant Tibetan antelopes in the Qiangtang National Nature Reserve. (Xinhua/Purbu Tsering)

An aerial drone photo taken on June 14, 2024 shows a view of the Tianshui River in the Qiangtang National Nature Reserve in southwest China's Xizang Autonomous Region. Tianshui River is an important migratory passage for pregnant Tibetan antelopes in the Qiangtang National Nature Reserve. (Xinhua/Purbu Tsering)

An aerial drone photo taken on June 15, 2024 shows a view of the Tianshui River in the Qiangtang National Nature Reserve in southwest China's Xizang Autonomous Region. Tianshui River is an important migratory passage for pregnant Tibetan antelopes in the Qiangtang National Nature Reserve. (Xinhua/Jigme Dorje)

An aerial drone photo taken on June 14, 2024 shows a temporary campsite of wildlife conservation workers by the Tianshui River in the Qiangtang National Nature Reserve in southwest China's Xizang Autonomous Region. Tianshui River is an important migratory passage for pregnant Tibetan antelopes in the Qiangtang National Nature Reserve. (Xinhua/Purbu Tsering)

An aerial drone photo taken on June 14, 2024 shows a temporary campsite of wildlife conservation workers by the Tianshui River in the Qiangtang National Nature Reserve in southwest China's Xizang Autonomous Region. Tianshui River is an important migratory passage for pregnant Tibetan antelopes in the Qiangtang National Nature Reserve. (Xinhua/Purbu Tsering)

An aerial drone photo taken on June 15, 2024 shows a view of the Tianshui River in the Qiangtang National Nature Reserve in southwest China's Xizang Autonomous Region. Tianshui River is an important migratory passage for pregnant Tibetan antelopes in the Qiangtang National Nature Reserve. (Xinhua/Jigme Dorje)

An aerial drone photo taken on June 15, 2024 shows trails left by Tibetan antelopes on the riverbed of the Tianshui River in the Qiangtang National Nature Reserve in southwest China's Xizang Autonomous Region. Tianshui River is an important migratory passage for pregnant Tibetan antelopes in the Qiangtang National Nature Reserve. (Xinhua/Jigme Dorje)

An aerial drone photo taken on June 15, 2024 shows Tibetan antelopes going across the Tianshui River in the Qiangtang National Nature Reserve in southwest China's Xizang Autonomous Region. Tianshui River is an important migratory passage for pregnant Tibetan antelopes in the Qiangtang National Nature Reserve. (Xinhua/Jigme Dorje)

An aerial drone photo taken on June 15, 2024 shows a view of the Tianshui River in the Qiangtang National Nature Reserve in southwest China's Xizang Autonomous Region. Tianshui River is an important migratory passage for pregnant Tibetan antelopes in the Qiangtang National Nature Reserve. (Xinhua/Jigme Dorje)