There is a sexual dimorphism in coloration. Male Cardinalis sinuatus are mainly gray with red located on the face, crest, wing, and tail (Scott 1983). The female is grayish brown, and is sometimes mistaken for a female Northern Cardinal, Cardinalis cardinalis (Oberholser 1974). The females have red highlights on the thighs and the wing linings (Tveten 1993). The bill is heavy and hooked in both the male and the female (Tveten 1993). In the male, the bill is orange yellow (Scott 1983), while the female's bill is a duller yellow (Tveten 1993). Both the male and female have the diagnostic tall crest on the head (Tveten 1993). The juvenile Pyrrhuloxia, male or female, resembles the female except the bill is darker (Oberholser 1974).
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes colored or patterned differently
Average mass: 32 g.
Average basal metabolic rate: 0.396495 W.