A cuckoo clock is a clock, typically a pendulum clock, that strikes the hours using small bellows and whistles that imitate the call of the Common Cuckoo bird in addition to striking on a wire gong.
The design of a cuckoo clock is now conventional. Most are made in the shape of a rustic birdhouse or chalet. They hang on the wall, and are housed in wooden cases, frequently decorated with carved leaves; sometimes deer and other animals are added. Most now have an automaton of the bird that appears through a small trap door when the clock is striking, and vanishes behind the door after the clock is done.
The bird is often made to move while the clock strikes, typically by means of an arm that lifts the back of the carving. Some have musical movements, and play a tune on a music box before striking the hours or half-hours. Musical cuckoo clocks frequently have other automata that move when the music box plays. The clocks are almost always weight driven; a very few cuckoo clocks are spring driven.
In recent years, fake quartz battery powered cuckoo clocks have been sold; these do not have genuine cuckoo bellows, and typically generate their striking sounds electronically. The weights are conventionally cast in the shape of pinecones. The pendulum bob is often another carved leaf. The dial is small, and typically marked with Roman numerals.
The cuckoo clock was invented in the Black Forest town of Schönwald, Germany, by Franz Ketterer in 1738. Ketterer designed the system of small bellows and whistles that imitates the Cuckoo's call, and added them to a standard Dutch clock. Later refinements of the design changed the clock's shape to the familiar birdhouse or chalet. The centre of their production continues to be in the Black Forest region of Germany, in the area of Triberg and Neustadt. The cuckoo clock is often wrongly associated with Switzerland.