Female Cardinal

Cardinals are incredibly easy to pick out the males from the females.

As cardinals are principally red and they take their name from Roman Catholic cardinals who wore red robes, if you are looking at a bright red, almost outrageously so, you are looking at a male cardinal.
They also have a reddish bill and a black mask covering their face.
Female cardinals, on the other hand are known for their subtler, some would say duller, pale brown coloring with just gentle reddish tips on the crest, tail and their wings. They have the same color of bill and the same black face mask.