The Splits
u Wren (Troglodytes troglodytes) to
   Winter Wren (Troglodytes hiemalis)
   Eurasian Wren (Troglodytes troglodytes)
   Pacific Wren (Troglodytes pacificus)
u Whip-poor-will (Caprimulgus vociferus) to
Eastern Whip-poor-will (Caprimulgus vociferus)
Mexican Whip-poor-will (Caprimulgus arizonae)
u Black Scoter (Melanitta nigra) to
Black Scoter (Melanitta americana)
Common Scoter (Melanitta nigra)