bright-rumped yellow-finch Sicalis uropygialis

Locally fairly common in the high Andes. Often in flocks, sometimes by the hundreds, and associates readily with other seed-eating birds. Feeds mainly on the ground, often on roadside gravel or in animal corrals. Distinctive in most of range, and distinguished readily from other yellow-finches by combination of silvery-gray cheeks and grayish back and flanks. The namesake bright rump is usually hidden and is a poor field mark. In Chile, Greenish Yellow-Finch occurs mainly at lower elevations.