Attractive warbler of cloud forest and stunted treeline forest in the Andes. Common member of mixed-species flocks. Ranges from far southern Colombia south to Bolivia. Has slaty-gray upperparts, yellow underparts, and bold yellow spectacles. Crown is rufous in the northern half of its range, but solid black in the southern half. Some birds in northern Ecuador and southern Colombia have a yellow forehead. Actively forages along branches, often spreading its tail exposing white outer tail feathers.