This species account is dedicated in honor of Julie Schnuck, member of the Cornell Lab of Ornithology's Administrative Board.
The Northern Cardinal (hereafter, cardinal), named for the male's red plumage, is found throughout eastern and central North America from southern Canada into parts of Mexico and Central America. It has taken advantage of moderate temperatures, human habitation, and provisioning at bird feeders to expand its range northward since the early 1800s and has been introduced to California, Hawaii, and Bermuda. A year-round resident, the cardinal is a common visitor to bird feeders in winter, and it has been chosen as state bird in 7 U.S. states.
The cardinal is strongly sexually dichromatic—the male brilliant red and the female primarily grayish tan. It is an omnivorous passerine with a diet consisting mainly of seeds, fruits and insects. Plumage color results from ingestion and deposition of carotenoid pigments obtained from the diet during molt and may signal mate quality. New research has shown that brighter males have higher reproductive success and territories with greater vegetation density, and that plumage brightness in both the male (breast color) and female (color of underwing coverts) is positively correlated with parental care (feeding nestlings).
Both male and female sing. Female song from the nest appears to provide the male with information about whether to bring food to the nest. Local song dialects are apparent: Mates and neighbors share most or all of their song repertoires, and repertoires diverge increasingly with increased distance.
The cardinal is socially monogamous, but recent DNA-fingerprinting studies reveal extra-pair paternity in 9–35% of young. Both male and female care for the nestlings, but the male contributes more food. Predation rates are high on nestlings and eggs, and only 15–37% of nests produce fledglings. The cardinal is parasitized by Brown-headed (Molothrus ater) and Bronzed (M. aeneus) cowbirds; egg removal by female Brown-headed Cowbirds may have a greater negative impact than does competition from cowbird nestlings.
To date, major areas of research on cardinals have included communication (e.g., Lemon and Scott 1966, Lemon 1966, Lemon 1967, Lemon 1968b, Lemon 1968c, Lemon 1975b, Lemon and Chatfield 1971, Ritchison 1986, Ritchison 1988b, McElroy and Ritchison 1996, Halkin 1997), parental care (Filliater and Breitwisch 1997, Linville et al. 1998), effects of nest parasitism (Scott 1963a, Scott 1977c, Scott et al. 1992, Scott and Lemon 1996, Eckerle and Breitwisch 1997), nest placement and defense (Filliater et al. 1994, Nealen and Breitwisch 1997), extra-pair fertilizations (Ritchison et al. 1994), molt (Scott 1967a, Wiseman 1977, Thompson and Leu 1994), and habitat and dispersal (e.g., Dow and Scott 1971, Conner et al. 1986). Research has been geographically biased to the eastern United States; more information is needed from populations in the southwestern United States and in Mexico.