The Northern Cardinal, a familiar and brightly colored songbird, is a common sight across backyards in North America. The cardinal pair exhibits a clear division of labor during the nesting process. The primary responsibility for keeping the eggs warm rests almost entirely with the female, while the male focuses on other crucial tasks to support the family unit.
The Male Cardinal’s Incubation Role
The female cardinal is the sole incubator of the eggs, a role facilitated by a specialized physiological feature. She possesses a “brood patch,” a bare area of skin on her belly that swells with blood vessels during the nesting season. This patch allows for direct, efficient transfer of body heat to the eggs, necessary for proper embryonic development.
The male cardinal does not develop a functional brood patch, making him poorly equipped to provide the sustained heat required for incubation. While a male may occasionally be observed sitting on the nest for very brief periods, this is rare and usually only occurs when the female leaves. Even when he covers the nest, his function is likely to serve as a guard rather than an effective heat source. The female sits on the clutch, which typically contains two to five eggs, for about 11 to 13 days until they hatch.
Supporting the Female During Nesting
The male’s main contribution during incubation is to provide for his mate, ensuring she rarely needs to leave the nest. This act, known as provisioning, is an extension of the courtship feeding behavior the pair engaged in earlier. By bringing food directly to the female, the male allows her to maintain nearly constant contact with the eggs.
His vibrant red plumage is used for territorial defense. The male aggressively guards the nesting territory against rival males and potential threats, often singing loudly to establish boundaries. This vigilance acts as an early warning system for the camouflaged female, who is protected by her duller coloration as she sits on the nest. This commitment frees the female to focus on incubation.
Caring for the Cardinal Chicks
Once the eggs hatch, parental duties shift dramatically, with both the male and female becoming active foragers. They initially feed the chicks a protein-rich diet of insects and spiders, necessary for the nestlings’ rapid growth. The nestlings remain in the nest for a relatively short time, typically fledging, or leaving the nest, just nine to 11 days after hatching.
The cardinal pair often raises two to three broods during a single breeding season, necessitating a further specialization of labor. As the female prepares for the next clutch, she begins building a new nest and laying a second set of eggs. At this point, the male assumes the primary responsibility for the first brood of fledglings.
The male continues to feed and protect the young birds for several weeks as they learn to forage for themselves and become independent. This efficient division of labor—where the male cares for the fledglings while the female incubates the next clutch—allows the cardinal pair to maximize the number of offspring they successfully raise within the season.