![](http://www.ecns.cn/hd/2020/01/08/33bc7d3ef1d342d488aebfe2b224b5a2.jpg)
Swans nest by the rivers at the Heihe Wetlands National Nature Reserve in Zhangye City, NW China’s Gansu Province, Jan. 6 to 7. A total of 140 swans were found at Heihe Wetlands National Nature Reserve in Zhangye City, NW China’s Gansu Province, Jan. 6 to 7. An investigation into the species, geo-location and so on was jointly conducted by staffs of nature reserve and Lanzhou University, in order to better protect these migrant birds.(Photo: China News Service/Zhang Xiqing)
![](http://www.ecns.cn/hd/2020/01/08/1b199eb011594bb8b2b879a6b7164f70.jpg)
Swans nest by the rivers at the Heihe Wetlands National Nature Reserve in Zhangye City, NW China’s Gansu Province, Jan. 6 to 7. A total of 140 swans were found at Heihe Wetlands National Nature Reserve in Zhangye City, NW China’s Gansu Province, Jan. 6 to 7. An investigation into the species, geo-location and so on was jointly conducted by staffs of nature reserve and Lanzhou University, in order to better protect these migrant birds.(Photo: China News Service/Zhang Xiqing)
![](http://www.ecns.cn/hd/2020/01/08/a4e07f64026f4ec59e75c3199044b647.jpg)
Swans nest by the rivers at the Heihe Wetlands National Nature Reserve in Zhangye City, NW China’s Gansu Province, Jan. 6 to 7. A total of 140 swans were found at Heihe Wetlands National Nature Reserve in Zhangye City, NW China’s Gansu Province, Jan. 6 to 7. An investigation into the species, geo-location and so on was jointly conducted by staffs of nature reserve and Lanzhou University, in order to better protect these migrant birds.(Photo: China News Service/Zhang Xiqing)
![](http://www.ecns.cn/hd/2020/01/08/268d7111062447adb122fdd30f0236e6.jpg)
Swans nest by the rivers at the Heihe Wetlands National Nature Reserve in Zhangye City, NW China’s Gansu Province, Jan. 6 to 7. A total of 140 swans were found at Heihe Wetlands National Nature Reserve in Zhangye City, NW China’s Gansu Province, Jan. 6 to 7. An investigation into the species, geo-location and so on was jointly conducted by staffs of nature reserve and Lanzhou University, in order to better protect these migrant birds. (Photo: China News Service/Zhang Xiqing)