Cuckoos are medium sized slender birds. They are generally well distributed all over the different continents except in the very cold Antarctic and the very dry parts of the Middle East and North Africa. These birds are best known for their wide repertoire of calls. Their calls are relatively simple, resembling whistles, flutes, or hiccups. They are meant to demonstrate ownership of a territory and to attract a mate.

German black forest cuckoo clocks are usually fitted with a call mechanism similar to that of the Common Cuckoo. Although these special clocks are closely associated with Black Forest, Germany, the first cuckoo clocks were not made there. German black forest cuckoo clocks started being manufactured years after a nobleman from Augsburg described the mechanism of this kind of clock in an article. This included the cuckoo bird which automatically opened its beak and moved its wings and tails. With this movement, we hear the whistle of the bird.