A cuckoo clock is a clock, typically pendulum driven, that strikes the hours using small bellows and whistles that imitate the call of the Common Cuckoo in addition to striking a wire gong. The mechanism to produce the cuckoo call was installed in almost every kind of cuckoo clock since the middle of the eighteenth century and has remained almost without variation until the present.
The design of a German cuckoo clock is now conventional. Most are made in the shape of a rustic birdhouse or chalet to hang on a wall. The wooden case is frequently decorated with carved leaves and animal heads. Most now have an automaton of the bird that appears through a small trap door while the clock is striking.
The bird is often made to move while the clock strikes, typically by means of an arm that lifts the back of the carving. There are two kind of movement: a one-day movement and an eight-day movement. Some have musical movements, and play a tune on a Swiss music box after striking the hours and/or half-hours. Musical German cuckoo clocks frequently have other automata which move when the music box plays. Cuckoo clocks are almost always mechanical weight driven movement; a very few are spring driven. The weights are made of cast iron in a pine cone shape. 1 Day Clocks need to be wound by pulling up the weights each day. 8 Day Clocks need to be wound by pulling up the weights every 7-8 days
In recent years, quartz battery-powered cuckoo clocks have been available. These do not have genuine cuckoo bellows. The cuckoo bird flaps its wings as it calls to the sound of running water in the background. The call is an actual recording of a cuckoo in the wild. During the cuckoo call the double doors open and the cuckoo emerges only at full hour, and they do not have a gong wire. One thing that is unique about the quartz cuckoos is that it has a light sensor, so when you turn your lights off at night, it automatically turns off the cuckoo call. The weights are conventionally cast in the shape of pine cones made of plastic, as well as the cuckoo bird and hands. The pendulum bob is often another carved leaf. The dial is small, and typically marked with Roman numerals.