One of the most identifiable birds in North America is the northern cardinal. Also called the redbird, common cardinal and Virginia nightingale, they are usually referred to simply as cardinals. Cardinals are beloved by backyard birders because of their bright red colors, joyful singing and year-round presence.

Cardinals are medium sized songbirds. Male cardinals are bright red, while females are light brown to gray with some red coloring on their wings, crests and tails. The red coloration of cardinals is a result of carotenoids in their feather structure ingested through what they eat. Both male and female cardinals have bright orange beaks. They have pointed crests of feathers on the tops of their heads and long tails. Male cardinals have black masks on their faces that extend to their chest. Female cardinals do not usually have black masks, but their faces may have dark markings. Young cardinals are similar in appearance to female cardinals, but have less red coloration and gray-black bills. Their beaks change from black, to a cream, then orange as they age.

Unlike most other songbirds, both male and female cardinals sing. They sing year-round to communicate. Male and female cardinals sing to each other. Male cardinals sing up to 200 songs an hour. They will sing to attract females or ward off intruders of their territory. Female cardinals often sing to get their mates to bring food to the nestlings. Cardinals also sing as alarm calls. Female cardinals have more elaborate songs than male cardinals. A cardinal can have over two dozen song variations. Cardinals from different areas can have very different songs.

Cardinals are granivorous, feeding mostly on grains. They also eat fruit and insects, foraging for different foods each season. They use their large, powerful bills to crack open seeds.

Cardinals are usually active during the day, especially in the morning and evening. They are often monogamous, mating for life. Cardinal couples remain together all year. In the winter months, most cardinals will flock together and roost together. During the breeding season they are very territorial. Cardinals can be extremely aggressive when defending their territories. Males cardinals violently chase away competitors. They may also attack their reflections in windows, mirrors and other reflective surfaces.

During the mating season, male cardinals show affection toward female cardinals by feeding them beak-to-beak. Cardinals are exceptional parents. Male cardinals will feed and care for mother cardinals during and following incubation. While caring for his family, the bright red colors of a father cardinal change to a duller shade of brown similar to the mother, acting as a camouflage. Mother cardinals lay one to five white eggs with brown spots. Cardinal babies are helpless when first born. Mother and father cardinals both collect food to feed them. Father cardinals are very protective of mother cardinals and their babies. Young cardinals follow their parents on the ground after they leave the nest for several days. They remain with their parents until they are able to fend for themselves.

Cardinals are preyed upon by a variety of predators, especially birds of prey. Snakes, other birds, rodents and cats prey on their eggs and chicks.

Cardinals can live over 15 years in the wild.

Cardinals are not rare and are protected under the Migratory Bird Act. While considered a common bird, even common bird populations are alarmingly declining due to irresponsible human activities. Loss of habitat, animal agriculture, pesticides and forestry are the largest threats to bird populations. Collisions with power lines, buildings and vehicles kills 900 million birds each year in the United States and Canada alone.