The term 'Cardinal Feature' refers to the physical characteristics of the Northern Cardinal, a species of bird native to North America. The crossword solutions for this term are 'BEAK' (4 letters), 'CREST' (5 letters), and 'Redhat' (6 letters). The BEAK of the Northern Cardinal is short and conical, and is used for cracking seeds and other food items. The CREST is a tuft of feathers on the top of the head, which can be raised or lowered depending on the bird's mood. Finally, the redhat is the bright red plumage on the head of the male Northern Cardinal, which is used to attract mates.