Like many bird names, cadrinals do not form a monophyletic group.
They are not even all in the same family including the typical cardinals in the genus Cardinalis (Cardinalidae) and the red-headed cardinals in the genus Paroaria (Thraupidae).
It is ambiguity all the way down - Thanks DNA.
 
Northern Cardinal (Cardinalis cardinalis)
 
Red-crested cardinal (Paroaria coronata)
 
Painted bunting Passerina ciris
 
Lazuli bunting (Passerina amoena)
 
Blue grosbeak (Passerina caerulea)
 
Black-headed grosbeak (Pheucticus melanocephalus)
   
 
Northern Cardinal (Cardinalis cardinalis)
	
 
	
Red-crested cardinal (Paroaria coronata)