Male: blue-grey above; black stripe from lores to nape; whitish cheeks and upper throat; all but central tail feathers black, with white markings; chestnut below. Female: duller chestnut below. Pairs or several, often with other small birds; restless climber; clings to bark and usually works up the tree stem, hammering with beak; also moves upside-down and sideways; may visit the ground.