Green’s Dictionary of Slang

charlie n.³

a fox.

1843		R.S. Surtees Handley Cross (1854) 262: I remembers a desp’rate cunnin’ Charlie that [...] arter runnin’ a wide ring, would return [...] and lie quiet.
1857		T. Hughes Tom Brown’s School–Days 8: A nice little gorse or spinney where abideth poor Charley, having no other cover to which to betake himself for miles and miles.