The song Blue-tail'd Fly was sung by a Master Watson at the Adelphi theatre in London in 1824. Long before it became a minstrel song. Of course there are several different sets of words -- all with the same chorus though. It was spread in Australia from 1850 by a solo black-face minstrel called Robert "Billy" Barlow. It has been collected here as sung to the tune of Early in the Morning. My father learned it from his family before 1900 and he told me that "Jimmy crack corn and I don't care" was about Jimmy the crow stealing and cracking open the corn. My thinking is that it was once a crow-scaring song from the British Isles before it was a minstrel song. Little kids often had crow-scaring as their first occupation in England and in America and many of their songs have been collected. They frequently have lines like the Blue-tail Fly chorus.