Birds
Northern Cardinal
Cardinalis cardinalis · also called cardinal, redbird, common cardinal
The northern cardinal is the crested, crimson songbird that lights up a snowy garden and a Christmas card alike. It is abundant, adaptable, loud, and — for a bird its size — surprisingly interesting, from the female’s song to the male’s habit of fighting his own reflection.
Overview
Northern cardinals live across the eastern and central United States, into southeastern Canada, and south through Mexico to Guatemala and Belize, in woodland edges, dense thickets, hedgerows, overgrown fields, parks, and suburban gardens — anywhere with shrubby cover for nesting and a supply of seeds and fruit. They do not migrate; a pair typically holds a territory year-round, and outside the breeding season cardinals gather in loose flocks at feeders.
Colour, crest, and bill
The male is unmistakable: bright red all over, with a black mask around a stout orange-red bill and a tall pointed crest. The female is a subtler warm grey-brown with red on the wings, tail, and crest — better camouflage for a bird that does most of the incubating. The heavy, conical bill is a seed-cracking tool, capable of husking sunflower seeds and even cracking cherry stones.
The red pigment is entirely dietary — from carotenoids in the bird’s food — so it doubles as an honest advertisement of a male’s condition.
Song
Northern cardinals are strong singers with a repertoire of clear, whistled phrases (“cheer-cheer-cheer,” “birdy-birdy-birdy”). Notably, the female sings too, often from the nest, and mated pairs duet, one bird answering or matching the other’s phrases. Female song, once treated as an oddity, is now understood to be an ancient songbird trait that many temperate species later lost.
Behaviour and breeding
In spring, territorial cardinals become famous nuisances, attacking their reflections in windows, mirrors, and car trim for hours on end. Pairs are largely monogamous within a season; the female builds a cup nest in a dense shrub or vine tangle, and both parents feed the chicks a high-insect diet. In the warm parts of the range a pair may raise two or three broods a year.
Status
The northern cardinal is Least Concern, extremely numerous (around 130 million), and increasing, having expanded its range well to the north over the past hundred years with the help of bird feeders and warmer winters. It is a favourite of birdwatchers and the official state bird of seven US states — more than any other species.
Northern Cardinal: common questions
Why is the male cardinal so red?
Its feathers are coloured by carotenoid pigments, which the bird cannot make and must get entirely from its diet — from red and orange fruits and from insects that ate carotenoid-rich plants. A male on a good diet grows the brightest, deepest red plumage, so his colour is an honest signal of his foraging ability and health, and females prefer redder males. Occasionally a genetic quirk or diet problem produces a yellow or orange "xanthochroic" cardinal.
Do female cardinals sing?
Yes, and it is unusual. In most North American songbirds only the male sings, but female northern cardinals have a full song, which they often deliver from the nest — possibly to tell the male whether to bring food, or to signal that all is well. Pairs also countersing, matching or answering each other's phrases. Female song is now thought to be the ancestral condition for songbirds, retained here and lost in many temperate species.
Why do cardinals attack windows and mirrors?
In the breeding season, a male (or female) cardinal that sees its reflection interprets it as a rival intruding on its territory and attacks, sometimes battering the same window, wing mirror, or shiny bumper repeatedly for days or weeks. It is not a sign of anything wrong with the bird — just very strong territorial instinct with no way to "win." Covering the reflective surface from the outside, or breaking up the reflection, usually stops it.
Are cardinals expanding their range?
Considerably. A century ago the northern cardinal was mainly a bird of the southeastern United States. It has since spread north and west into New England, the Great Lakes states, southern Canada, and the Great Plains, and its range is still growing. The main drivers are thought to be the huge increase in backyard bird feeding, which helps birds through northern winters, along with milder winters and the spread of edge and shrubby habitat.