Common loon - breeding adult. Photo: Tammy Pick/Audubon Photography Awards 1 of 17

Common loon - molting adult. Photo: Randy Richard/Audubon Photography Awards

Common loon - non-breeding adult. Photo: Brian Kushner

Red-throated loon - breeding adults. Photo: Ken Archer/Audubon Photography Awards

Red-throated loon, non-breeding adult. Photo: Becky Matsubara/Flickr (CC BY 2.0)