A �toy� stop which imitates the call of the cuckoo bird using two pipes pitched a major or minor third apart and blown successively. It was, according to Williams, found mainly in the 16th and 17th centuries throughout Europe, and as late as the mid-19th century in some parts of Spain, Italy and southern Germany.
No examples of Cuckoo, Cukuk, Gukuk, or Cuckguck are known. Contributions welcome.