I think maybe they cover Peter Rowans version of the "the Cuckoo", but this is from Wiki-
"The Cuckoo" is a traditional English folk song. It has been covered by many musicians in several different styles. An early notable recorded version was performed by Appalachian folk musician Clarence Ashley with a unique banjo tuning.
The title of the song has multiple variations, including The Coo-Coo, The Coo-Coo Bird, The Cuckoo Bird, and The Cuckoo Is A Pretty Bird.
Lyrics usually include the line (or a slight variation):
The cuckoo is a pretty bird, she sings as she flies; she brings us glad tidings, and she tells us no lies.
According to Thomas Goldsmith of The Raleigh News & Observer, "The Cuckoo" is reportedly descended from an old folk ballad; it's an interior monologue where the singer "relates his desires — to gamble, to win, to regain love's affection."