"Bunny had a maddening habit of breaking out into choruses of 'The Farmer in the Dell'"

'The Farmer in the Dell' is a children's nursery rhyme, probably originating in Germany. In England, the same tune accompanies the song 'The Farmer Wants a Wife.' The song begins:

The farmer in the dell

The farmer in the dell

Hi-ho, the derry-o

The farmer in the dell...

Listen to this song on Spotify.