by Alvaro Jaramillo and David Beadle
The genus Carpodacus which includes the Purple, Cassin’s and House finches of North America and many Asian species, consists of sexually dimorphic birds with males showing obvious red on the plumage while the females are duller, brown and streaked. This article deals largely with the separation of Purple Finch C.purpureus and Cassin’s Finch C.cassinii in this duller streaked plumage. House Finch C.mexicanus will be dealt with at a lesser level of detail as it is not nearly as difficult an identification problem. Purple and Cassin’s finches are closely related “sister species” while House Finch is genetically quite distant from them (Marten and Johnson 1986).