Audubon's "Extra" Warbler

This is a fine reproduction of a very unusual painting by famed ornithological artist John James Audubon. The original name of this work is "Pine Swamp Warbler" and the two birds were labelled male and female. Today we know that there is no such species as the Pine Swamp Warbler, and its not because it went extinct. Audubon made a mistake; it later came to light that the birds in this painting are actually a pair of female (or possibly a female and a juvenile) Black-throated Blue Warblers. This species of warbler exhibits extreme sexual dimorphism, meaning male and female plumages are radically different. When Audubon painted the Birds of America, this mistake slipped in and for a while we had an "extra" warbler species.