The northern flicker or common flicker (Colaptes auratus) is a medium-sized bird of the woodpecker family. It is native to most of North America, parts of Central America, Cuba, and the Cayman Islands, and is one of the few woodpecker species that migrate. Over 100 common names for the northern flicker are known, including yellowhammer (not to be confused with the Eurasian yellowhammer (Emberiza citrinella)), clape, gaffer woodpecker, harry-wicket, heigh-ho, wake-up, walk-up, wick-up, yarrup, and gawker bird. Many of these names derive from attempts to imitate some of its calls.
The northern flicker may be observed in open habitats near trees, including woodlands, edges, yards, and parks. In the western United States, one can find it in mountain forests all the way up to the tree line. The northern flicker generally nests in holes in trees like other woodpeckers. Occasionally, it has been found nesting in old, earthen burrows vacated by belted kingfishers (Megaceryle alcyon) or sand martins (Riparia riparia). Both sexes help with the nest excavation. The entrance hole is about 8 cm (3 in) in diameter, and the cavity is 33–41 cm (13–16 in) deep. The cavity widens at the bottom to make room for the eggs and the incubating adult. Inside, the cavity is bare except for a bed of wood chips for the eggs and chicks to rest on. Once the nestlings are about 17 days old, they begin clinging to the cavity wall rather than lying on the floor. They can create cavities inside homes, especially homes of stucco or weak wooden siding.
