Roger Tory Peterson described purple finches as "sparrows dipped in raspberry juice." They are patchy red all the way down to the tail, with very little brown on them; as opposed to house finches which have a red breast and brown wings and head. Their songs are also different, listen to the Purple finch here, and the house finch here, (When you get there, you'll need to scroll down for both).
Purple finch (Carpodacus purpureus). Photo: Thomas Klak |
House finch (Carpodacus mexicanus) Photo: Birdfreak.com |
House finches have distinct brown stripes on their lower body and a very small red patch above the tail. Their cheeks are brown, not red.