Northern cardinals are a familiar sight and sound across North America, recognized for their striking appearance and melodious songs. Common in backyards, parks, and dense shrubbery, they are easily observable. Their widespread presence makes their reproductive behaviors a subject of interest.
Cardinal Breeding Season
The breeding season for Northern cardinals spans from early spring through late summer, typically March to August. In warmer southern regions, nesting can begin as early as February. This extended period allows for multiple nesting attempts.
Increasing daylight hours and rising temperatures signal the onset of breeding. Males establish and defend territories with their songs, while females assess potential nesting sites.
The Nesting Cycle
Once a suitable location is chosen, the female cardinal undertakes the construction of the nest, a process that typically takes three to nine days. This cup-shaped structure is usually well-concealed in dense shrubs or low trees, often three to ten feet above the ground. The male may assist by bringing materials, but the female primarily shapes the nest using twigs, grass, and other plant fibers.
Following nest completion, the female lays a clutch of two to five eggs, usually one egg per day. These eggs are whitish to pale bluish or greenish white and marked with brown or gray speckles. Incubation, performed almost entirely by the female, lasts approximately 11 to 13 days.
After hatching, the altricial chicks remain in the nest for about 7 to 13 days before fledging, or leaving the nest. Both parents share feeding duties during this time, providing insects to their rapidly growing young. As the fledglings become more independent, the male often assumes primary care, allowing the female to prepare for another nesting attempt.
Factors Influencing Breeding and Brood Frequency
Northern cardinals commonly raise two to three broods each year, though some pairs may attempt a fourth brood under favorable circumstances. The number of successful broods often depends on various environmental and biological factors. Regional differences play a role, with cardinals in southern areas sometimes producing three broods annually, while those in northern climates typically have two.
Food availability significantly influences breeding success and the number of broods. Ample food resources, particularly insects for the young, support the energy demands of raising multiple clutches. Local climate variations, such as an early spring or prolonged warm weather, can extend the breeding season, allowing for more nesting attempts. The presence of predators, which can lead to nest failure, may also prompt cardinals to re-nest, impacting the overall frequency of broods.