Migrant birds fly over Ulan Suhai Lake in Bayan Nur, north China's Inner Mongolia Autonomous Region, Oct. 28, 2020. The wetland of Ulan Suhai Lake is an important breeding location for migrant birds. (Xinhua/Lian Zhen)

Migrant birds are seen at Ulan Suhai Lake in Bayan Nur, north China's Inner Mongolia Autonomous Region, Oct. 27, 2020. The wetland of Ulan Suhai Lake is an important breeding location for migrant birds. (Xinhua/Lian Zhen)

Aerial photo taken on Oct. 28, 2020 shows Ulan Suhai Lake in Bayan Nur, north China's Inner Mongolia Autonomous Region. The wetland of Ulan Suhai Lake is an important breeding location for migrant birds. (Xinhua/Lian Zhen)

Migrant birds fly over Ulan Suhai Lake in Bayan Nur, north China's Inner Mongolia Autonomous Region, Oct. 28, 2020. The wetland of Ulan Suhai Lake is an important breeding location for migrant birds. (Xinhua/Lian Zhen)