I had never heard this expression until today, when I just heard it in an old western film. Is it strictly an American colloquialism?
n. U.S. colloquial a horse of unknown paternity; also, a foundling; an illegitimate child.
1895 Dial. Notes 1 395 Woods colt, foundling, Winchester, Ky.
1903 Dial. Notes 2 337 Woods colt, a horse of unknown paternity. Also applied to a person of illegitimate birth.
1913 H. Kephart Our Southern Highlanders xiii. 294 A bastard is a woods-colt or an outsider.
1959 W. Faulkner Mansion i. 4 Will Varner was going to have to marry her off..quick, if he didn’t want a woods colt in his back yard next grass.