(Tichodroma muraria), bird of the mountains of southern Europe to central Asia, largest member of the family Sittidae (order Passeriformes). About 17 cm (6 ¹/₂ inches) long and mostly gray with broad, rounded black wings having central red patches, it has a long, thin, downcurved bill. In searching for insects on cliffs, it ascends jerkily while flicking its wings. In winter it may visit lowlands and climb the walls of city buildings.