The Northern Cardinal (Cardinalis cardinalis) is a member of the cardinal family of birds in North America. The bird's name comes from the red-robed Roman Catholic Cardinals. Its crested head is also said to resemble a bishop's mitre. Cardinals have been also referred to as "Redbirds" and "Virginia nightingales". Cardinals were once popular cage birds for their bright color and rich, varied songs.

The Northern Cardinal is a mid-sized songbird with a body length of 8.3 to 9 inches (21-23 cm) and a wingspan of 10-12 in (25-31 cm). It weighs about 1.6 ounces (45 g). Males are slightly larger than females.

The male is a brilliant crimson red with a black face mask over the eyes and extending to the upper chest. Females are a fawn color, with mostly grayish-brown tones and a slight reddish tint in the wings and tail feathers. The face mask of the female is gray to black, and is less defined than that of the male. Both sexes possess prominent raised crests and strong bright coral-colored beaks. Young birds, both male and female, show the coloring of the adult female until the fall, when they will molt and grow their adult feathers.

Cardinals are abundant across the eastern United States from Maine to Texas and in Canada in the provinces of Ontario, Quebec, and Nova Scotia. Their range extends west to the U.S.-Mexico border and south through Mexico to the Isthmus of Tehuantepec, northern Guatemala, and northern Belize. They were introduced to Bermuda in 1700. They have also been introduced in Hawaii, and Southern California. Their natural habitats are woodlands, suburbs, gardens, swamps and thickets.

These birds are permanent residents throughout their range, although they may relocate to avoid extreme weather or if food is scarce.

Cardinals are a territorial song bird. The male sings in a loud, clear whistle from a tree top or other high location to defend his territory. He will chase off other males entering his territory.

Cardinals learn their songs, and as a result the songs vary regionally. Cardinals are able to easily distinguish the gender of a singing cardinal by its song alone. Interestingly, however, male cardinals can learn songs from female cardinals, and vice versa, suggesting that differences in song between the sexes may be due to hormonal differences.

Cardinals have a distinctive alarm call, a short metallic 'chip' sound. In some cases they will also utter a series of chipping notes. It is often easy to locate Cardinals by their alarm call, since they will make it readily when humans walk nearby.

Northern Cardinals' diet consists mainly (up to 90 percent) of weed seeds, grains, and fruits. During the summer months, they show preference for seeds that are easily husked, but are less selective during winter, when food is scarce. Northern Cardinals also will consume insects, and feed their young almost exclusively on insects.