Why Cardinals Are Red
The diet of a Northern Cardinal consists mainly of seeds, fruits and insects (average annual consumption is 29% animal and 71% vegetable matter). As fall progresses, the proportion of vegetable matter in its diet increases until it reaches a high of 88% during winter. The red plumage color of both males and females (females have some red feathers in wings and tail) results from the ingestion of carotenoid pigments obtained from their diet during the fall molt (September/October). Fruits and insects are high in carotenoids, while most seeds are poor sources. According to Cornell Lab of Ornithology, 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).
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