3ISSF; western, eastern, and cozumel. Plumage varies, with breeding (MAR-AUG) male sporting a black supercilium and forehead. M/F differ, but only in breeding plumage (see above). Non-breeding plumages are alike. Feature coverage of BGGN is a bit odd; effectively breeding is the only identifiable time the species differs but would be odd to have breeding tags for m/f and then a generic adult/non-breeding tag. Can re-visit in future if difference makes sense.