Cao Hai Lake is a high-altitude wetland at 2,171 metres above sea level in the far northwest of Guizhou, and between late October and early spring it serves as a wintering ground for several hundred black-necked cranes along with over 170 other bird species. The lake covers about 25 square kilometres, fringed by reedbeds and shallow marshes where the cranes feed on roots, small fish, and invertebrates. On clear winter mornings, when the high-altitude light is sharp and low, the cranes gather in groups of dozens on the open water — sometimes with a backdrop of frost-rimmed reeds and the high plateau visible beyond.
The standard way to experience the lake is by the narrow wooden boats paddled by local farmers along channels through the reedbeds. The boats move quietly, the cranes tolerate them at close range, and the hour-long circuit covers the main crane feeding areas. Beyond cranes, the lake hosts bar-headed geese, black storks, and a variety of ducks and waders in winter. The entrance fee covers access to the lake shore; boats are hired separately and cost around ¥50–80 for an hour.