The Northern Cardinal male is clearly brighter in color than the Pyrrhuloxia (say: 'peer uh LOX eee uh') of both sexes. The 'trick' is telling a female Northern Cardinal (much grayer/browner/duller than the male) from a Pyrrhuloxia of either sex. For identification on the fly (pun intended), look to the beak. Both species have short, solid, seed-cracking beaks; but Northern Cardinals have beaks of red/orange; and Phyrrhuloxia beaks are yellowish at their brightest (in the male, usually). All photos from Red, er, Ned Harris.