The flash of a brilliant red cardinal against a snowy white landscape or the cheerful ‘cheer-cheer-cheer’ song echoing through a spring garden are quintessential sights and sounds across much of the United States. These beloved birds, with their striking plumage and vocal presence, are often symbols of hope, joy, and even enduring love. But for many who observe these captivating creatures, a common question arises: Do cardinals truly mate for life? The notion of lifelong pair bonds holds a romantic appeal, yet the realities of the avian world are often more nuanced than our human interpretations.
When talking about cardinals in the United States, most people are referring to the Northern Cardinal. This is by far the most widespread and recognizable cardinal species in the country, known for the male’s vibrant red plumage. However, there are two other species within the genus Cardinalis that are found in parts of the United States.
Northern Cardinal
The Northern Cardinal (Cardinalis cardinalis) is the iconic red bird found across the eastern and central United States, and extending into the Southwest. Males are brilliant red with a black face mask, while females are more muted brown with reddish accents. They typically breed between March and September, often raising two to three broods per year. The first nest can be started even before the last snowmelt in some areas.
Courtship begins in early spring. Males display by raising their crests, swaying, and singing softly to attract a female. A key courtship behavior is the male courtship feeding the female, passing food (often seeds) beak-to-beak, which strengthens their bond and shows his ability as a provider.
Once the pair is established, the female is primarily responsible for building the nest, a cup-shaped structure made of twigs, bark strips, and grass, lined with finer materials like rootlets, plant fibers, and animal fur. Nests are usually well-hidden in dense shrubs or small trees, typically 3-10 feet above the ground. Females lay 1-5 (usually 3) white to greenish eggs with spotting. Incubation, performed solely by the female, lasts 11-13 days. The male brings food to the incubating female. During the breeding season, pairs are quite territorial, with males aggressively defending their territory from other males and females sometimes chasing other females.
Both parents feed the chicks, primarily with insects. Chicks fledge (leave the nest) 7-13 days after hatching. Parents continue to feed the fledglings for another 25-56 days until they become independent. The male sometimes takes over feeding older fledglings, allowing the female to start the next brood.
Do they mate for life?
Northern Cardinals are generally considered serially monogamous, meaning they form a pair bond for one breeding season or perhaps several. They often stay together year-round, even through winter, reinforcing the perception of a lasting bond. While some pairs may stay together for multiple years, even for life, it’s not a universal rule. Studies have shown that pairs can separate during breeding seasons. Despite being monogamous, extra-pair copulations (where individuals mate with birds other than their primary partner) occur, with DNA studies indicating that a significant percentage (9-35%) of nestlings may not be fathered by the female’s social mate.
Pyrrhuloxia
The Pyrrhuloxia (Cardinalis sinuatus) is also known as the ‘desert cardinal’. This species is found in the southwestern United States (Arizona, New Mexico, and Texas) and Mexico. It’s primarily gray with red accents on the crest, wings, and tail, and has a distinctive yellowish, stubby bill.
As part of their courtship and mating, males defend territories throughout the breeding season. Once pair bonding has occurred, this striking cardinal will typically nest during May, June, and July. Similar to Northern Cardinals, the female primarily builds a cup-shaped nest of twigs, weeds, and bark strips, lined with fine grass and fibers. Nests are placed 4-15 feet above the ground, often in thorny shrubs or low trees. Females lay 2-5 (usually 3-4) pale grayish-white to greenish-white eggs with brown and gray spots. Incubation is done by the female for about 14 days, with the male often feeding her on the nest. Both parents feed the nestlings, which fledge around 10 days after hatching.
Do they mate for life?
As this is a less common cardinal, studies into their breeding process and the longevity of pairs are not as in-depth. The information is a bit mixed, but sources suggest that Pyrrhuloxia primarily share a pair bond only during the breeding season. They often break up in the non-breeding season to join loose, often mixed-species flocks that wander to find food in their arid habitats. Other sources, however, do state they typically mate for life, but the consensus leans towards seasonal pair bonds, contrasting with the Northern Cardinal’s more extended associations.
Red-crested Cardinal
The even less common Red-crested Cardinal (Paroaria coronata) is sometimes seen in the contiguous U.S., particularly in Florida and Hawaii. Originally from South America, their presence in the U.S. is often due to escaped captive birds. They have a striking red head and crest, with a gray body and white underparts.
In their native range, breeding is often from October to November. In introduced populations in the U.S. (e.g., Florida, Hawaii), it’s typically June to September. The male constructs a cup-shaped nest of grass and twigs, lined with finer material. Nests are usually in the fork of a tree, 6-20 feet from the ground.
The female lays 2-5 eggs, which are greenish-white with streaks. Incubation (12-13 days) is done by the female, but both parents feed the chicks, which fledge after about 2 weeks and are independent within another month.
Do they mate for life?
Red-crested Cardinals are generally considered monogamous and are often stated to mate for life in their native range. Pairs remain exclusively together during the breeding season and maintain continuous vocal contact.
What Influences Partner Bonds?
It is interesting that these species are so similar but also so different. Their shape and crests look strikingly common, while their colors contrast markedly. Regarding which species mate for life, the picture is not definitive, but it does seem that there are differences between the 3 varieties. So what influences whether these birds mate for a season, a year, or for life?
Firstly, a huge factor is the lifespan of the birds involved. If one member of the pair dies, the surviving bird will quickly find a new mate. Next, and quite logically, if a pair has successful nesting seasons, they are more likely to stay together. Conversely, unsuccessful breeding (e.g., nest failure, predation) can lead to separation and the birds seeking new mates.
While socially monogamous, studies have shown that Northern Cardinals, for instance, do engage in extra-pair copulations, where a bird mates with an individual outside its bonded pair. This can occur to improve overall fledgling success. Male cardinals aggressively defending their territory and mate may reduce the likelihood of these events. This activity goes back to the aim of mating – to pass on the strongest genes to the next generation of birds. More determined males and more sneaky females may engage in this extra ‘marital’ activity to ensure the best chance of good genes in their chicks.
Final Thoughts
In summary, while the Northern Cardinal is widely perceived as mating for life, the reality is more often serial monogamy for a season or a few years. The Pyrrhuloxia typically forms seasonal pair bonds, and the introduced Red-crested Cardinal appears to maintain lifelong monogamous pairs.
