Large, streaky tinamou of upper elevations of the east side of the Andes. The highland version of Red-winged Tinamou, similar in voice and habits. Fairly rare and local in tall grass in the high Andes from NW Argentina to the La Paz area in Bolivia. Prefers steep hillsides and slopes, largely absent from the altiplano. From other montane tinamous by characteristic plaintive, two part whistled song, for which it is named (“HUAY-co”). Shy and retiring, can be quite difficult to see, most often found by voice.