The stunning red color of the male northern cardinal is one of the most recognizable sights in North American wildlife. This brilliant color makes them easy to spot and is one of the reasons they are so beloved. But why are cardinals red, and what purpose does this color serve?
Pigments and Diet: The Source of Red Feathers
The red color in male cardinals’ feathers comes from carotenoid pigments, which are found in the seeds, berries, and fruits they eat. These pigments are not naturally produced by the birds but are absorbed from their food. Once ingested, these pigments are deposited in the birds’ feathers as they grow, creating their striking red color. Interestingly, a cardinal’s shade of red can vary based on diet quality; males with access to more carotenoid-rich food sources, like certain berries, will often have more vibrant red feathers.
Males Are Red for Mating and Territory
In many bird species, males are more brightly colored than females, and cardinals are no exception. Male cardinals use their bright red feathers to attract mates and establish territory. Females, who are a softer brown with subtle red accents, are more camouflaged, helping them stay safer while nesting. For the males, however, their bold color serves as a visual signal to both potential mates and rival males.
Attracting Mates
Female cardinals prefer mates with bright red plumage, as the intensity of a male’s color often indicates his health and access to good food sources. This preference has led to brighter feathers being advantageous for male cardinals over time, as those with more vibrant feathers are more likely to attract mates and pass on their genes.
Defending Territory
The bright red color also serves as a warning to other males. Male cardinals are territorial and will fiercely defend their space from other males, especially during the breeding season. A flash of red signals to other males that the area is claimed and protected. Males will even attack their own reflection if they spot it, mistaking it for a rival trying to invade their territory.
Why Aren’t Female Cardinals Red?
Female cardinals are more of a brownish-gray with red accents, and this difference in coloration helps with camouflage. Since females are responsible for building nests and incubating eggs, their subdued color provides protection from predators, blending in with tree branches and bushes.
The Role of Red in Evolution
Over time, natural selection has favored red plumage in male cardinals because of its role in mating and territory defense. By eating foods rich in carotenoids and displaying vibrant colors, male cardinals are better able to attract mates and assert dominance over their territory. This evolutionary pressure has led to their famous bright red feathers, making them one of the most visually striking birds in North America.
A Lasting Symbol of Beauty and Resilience
The cardinal’s red color serves not only as a means of survival and attraction but also contributes to their symbolism in human culture. Their bright, resilient presence in winter landscapes has made them a symbol of beauty, warmth, and endurance, qualities that have endeared them to people for generations.
In essence, the cardinal’s red feathers are the result of a mix of diet, evolutionary advantage, and the role of natural selection in reinforcing traits that help these beautiful birds survive and thrive.