E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Gouk or Gowk.
In the Teutonic the word gauch means fool; whence the Anglo-Saxon geac, a cuckoo, and the Scotch goke or gouk.
Hunting the gowk [fool], is making one an April fool. (See APRIL.)
A gowk storm is a term applied to a storm consisting of several days of tempestuous weather, believed by the peasantry to take place periodically about the beginning of April, at the time that the gowk or cuckoo visits this country.
That being done, he hoped that this was but a gowk-storm.Sir G. Mackenzie: Memoirs, p. 70.