Northern Cardinal

Red is a recipe

Male northern cardinals are brilliant red. Females are mostly grayish tan, with red on the wings, tail and crest. That red is not made from scratch. It comes from carotenoids, pigments the bird eats, changes chemically inside its body and deposits in new feathers while it molts, which is when it swaps old feathers for fresh ones.

Colour may carry a message. Redder males have denser vegetation on their territories, and may be larger and have higher reproductive success. Studies in cities and the countryside have found different links between colour and success, so the message is not simple.

The yellow cardinal Researchers once studied a cardinal with yellow feathers. They lacked all four of the usual red pigments and held yellow ones instead, including lutein, a yellow pigment from food. The mutation seems to have impaired only one class of chemical reaction, leaving the rest working.

Loud songs from both sexes

Both males and females sing. The songs are loud, whistled phrases that defend territory and court mates. Mates and neighbours share most or all of their songs, and the repertoires drift apart with distance, which makes local dialects. Chip calls work as contact calls and alarms, and raising and lowering the crest, the tuft of feathers on the head, also signals alarm. Both sexes attack their own reflections in windows and car mirrors, most often in spring and early summer, when they are defending their territory.

Small bird, seed cracker

An adult is 20.9 to 23.5 cm long, averages 42 to 48 g and has an average wingspan of 30.5 cm. The bill is thick and cone-shaped, and cardinals prefer seeds that are easily husked, meaning the shell comes off with little work. The diet is mainly seeds, fruits and insects, and parents feed their chicks almost exclusively insects.

A backyard success story

Cardinals live across eastern, central and parts of southwestern North America, from southern Canada to northern Central America, and have been introduced to Hawaii, southern California and Bermuda. The range has been expanding northward since at least the mid-1800s, as the birds took advantage of moderate temperatures, human habitation and bird feeders. The IUCN rates the species Least Concern.

Life is risky at the nest. The female incubates the eggs for 11 to 13 days, predators take many eggs and nestlings, and only 15 to 37 percent of nests produce fledglings, the young that leave the nest. The oldest recorded cardinal was a female, 15 years and 9 months old when she was found in Pennsylvania.