In ornithology, the plumage of birds.--Rev. John Boag's Imperial Lexicon, c. 1850
Tenbury Cuckoo Fair
There is a belief in [Worcestershire] that you never hear the cuckoo till Tenbury Fair day or after Pershore Fair day, which is the 26th of June. It is a popular belief in Norfolk that whatever you are doing the first time you hear the cuckoo, that you will do most frequently all the year. Another is that unmarried person will remain single as many years as the cuckoo, when first heard, utters its call. ... There are in England remnants of other old customs marking the position which the cuckoo held in the superstitions of the Middle Ages. In Shropshire, till very recently, when the first cuckoo was heard, the labourers were in the habit of leaving their work, making holiday of the rest of the day, and carousing in what they called the cuckoo ale. Among the peasantry in some parts of the kingdom, it is considered to be very unlucky to have no money in your pocket when you hear the cuckoo's note for the first time in the season.--W. & R. Chambers' Book of Days, 1864
But then really, do labourers need a reason to leave their work, make holiday the rest of the day, and carouse in ale?