Green’s Dictionary of Slang

(US black) Old Crow whisky.

1994		C. Major Juba to Jive 138: Dirty Bird n. (1940s–1950s) nickname for Old Crow whiskey.
1996		E. Sherwin ‘Printed Matter’ [synd. col.] Banks knows he’s jeopardizing his marriage and the love of his wife and daughter, but the seductive pull of [...] Old Crow (also known as Dirty Bird) is nearly too much for him to resist.