The northern cardinal is one of the most recognizable and popular backyard birds in North America. The bright red plumage of the male cardinal against the more muted brownish-gray plumage of the female is a classic example of sexual dimorphism in birds. However, this iconic difference in coloration between male and female cardinals is not present immediately after the birds hatch. Newly hatched cardinal nestlings have drab gray down feathers that obscure their future vibrant plumage. So what colors do immature male cardinals display as they molt from their initial juvenile plumage to their distinctive scarlet red adult feathers? Let’s take a closer look at the fascinating progression of color changes in immature male cardinals.
Plumage Changes from Hatchling to Adult
Cardinals hatch with sparse, gray downy feathers. At around 2 weeks old, their juvenile plumage starts growing in. Both male and female fledglings initially have similar-looking feathers: brownish-gray with some reddish-brown on the crest, wings, and tail.[1] The reddish hues may be somewhat more pronounced on male nestlings, but in general the sexes appear quite similar.
After leaving the nest at about 2 weeks old, the young cardinals undergo several molts over their first year as their plumage slowly matures.[2] Around 1-2 months old, immature males develop rosy red feathers on their faces, crests, tails, and wings. The breast feathers turn a tan-pink color. Immature females undergo similar molts but retain more gray-brown hues.
By around 6 months old, immature males have a nearly full set of red feathers on the face, crest, tail, and wings. However, the breast and belly feathers are still a distinctive tan-pink color, lacking the vibrant crimson-red hue of adult male cardinals. The bill of immature males also starts turning orange-red instead of the gray-pink of females.
At approximately 1 year old, male cardinals complete their final molt to full adult plumage. The breast and belly feathers transition to the bright scarlet-red that distinguishes mature males. The bill also becomes a vivid orange-red. Meanwhile, adult females retain their subdued brownish-gray feathers with touches of dull red.
So in summary, immature male cardinals transition from an initial gray down through a brown juvenile plumage, then acquire increasing amounts of distinctive red feathers on the face, crest, wings, and tail. The breast remains tan-pink before finally turning brilliant red in mature adults.
Differences Between Adult Males, Females, and Immatures
Plumage Area | Adult Male | Adult Female | Immature Male |
---|---|---|---|
Head | Bright red | Grayish-brown | Pinkish-red |
Crest | Bright red | Grayish-brown with some red | Pinkish-red |
Breast | Bright red | Light brown | Pinkish-tan |
Belly | Bright red | Light brown | Pinkish-tan |
Wings | Mostly bright red | Gray-brown with some red | Pinkish-red |
Tail | Bright red | Gray-brown with some red | Pinkish-red |
Bill | Orange-red | Pinkish-gray | Pinkish-orange |
This table summarizes the key differences in plumage coloration between adult male, adult female, and immature male cardinals. While adult males have uniformly brilliant red feathers, immature males display a mix of gray-brown juvenile feathers and emerging pinkish-red adult plumage. The most notable difference is the tan-pink breast and belly of immatures compared to the vivid crimson-red on adults.
Why Do Male and Female Cardinals Have Different Colors?
The differing plumage between male and female Northern cardinals is an excellent example of sexual dimorphism. Males and females have evolved distinct feather coloration due to differences in their reproductive roles and behaviors.[3]
The bright red plumage of the males doesn’t serve a camouflage purpose. Rather, it has evolved through sexual selection – females are attracted to the brilliant colors of fit and healthy males. Males with the brightest red feathers are signaling their genetic strength.
The subtler brownish plumage of females does provide more camouflage while they incubate eggs in nests. Drab feathers reduce the risk of predators spotting the nests. Females visit the nest less frequently than the brightly colored males, who are responsible for bringing food to the incubating mates and nestlings.
Immature males start off with camouflaged brown juvenile plumage similar to females. But as they mature, sexual selection pressures drive the transition to increasingly bright red feathers attractive to potential mates.
Geographic Variation in Cardinal Plumage
While Northern cardinals of North America exhibit strong sexual dimorphism, this is not true of all cardinal species worldwide. The South American Yellow-billed Cardinal has males and females that appear nearly identical with bright red plumages.[4] However, in parts of its range, yellow coloration replaces red in both sexes. This may be due to differences in carotenoid pigments available in the diet.
There are also geographic variations in the shade of red shown by North American Northern Cardinals. Birds in Florida and further south have deeper, richer crimson plumage compared to the more orange-red hues of cardinals farther north. Researchers theorize the warmer climates allow cardinals to allocate more carotenoids to feather production versus using them for health reasons.
So while vivid red plumage in male cardinals serves as a sexually-selected indicator of fitness, environmental factors can also influence the exact shades of coloration. The diet, climate, and carotenoid pigment availability where cardinals live impacts how their signature red feathers develop.
Conclusion
The reddish feathers we associate with male Northern Cardinals are not present immediately after hatching. Immature males transition from an initial gray-brown juvenile plumage to the distinctive crimson-red of adults through a series of molts in their first year. Intermediate stages include pinkish-red feathers on the face, crest, wings, and tail, with tan-pink on the breast changing to scarlet-red last. Understanding the nuances of cardinal plumage development provides deeper insight into how sexual selection and environmental adaptation shape bird coloration. Paying careful attention to the subtleties of feather coloring can also help birders accurately distinguish between adult males, females, and immatures. Noting the variations in cardinal shades across their range reveals the intriguing interplay between evolution, physiology, and habitat. So the next time you see a flash of red in a tree, take a closer look to see if it’s the brilliant crimson of an elder cardinal or the softer pinks of a younger bird.