What causes cardinals (males) to vary in color?

The quality of pigmentation strongly effects reproductive potential of cardinals as females go for the most assertive and aggressively territorial males. The striking red color is an indicator of physical and genetic fitness and is used as an advertisement for superior genes by by hopeful males vying for female attentions. read more

Cardinals owe their crimson color thanks to a pigment called zoonerythrin. Any mutation in the genes responsible for the expression of this pigment can change the plumage pigmentation levels and patterns. read more

When considering color, adult male northern cardinals are significantly more bold than the ladies of their species. The males have intense red feathers on their bodies, with the contrast of black coloration on their faces. The obvious, instant difference in plumage coloring is one of the primary components of the species' sexual dimorphism. read more

Even many children can identify the male northern cardinal when it pays a visit to a nearby tree branch or bird feeder. Its vibrant red coat is named after the lustrously red coats traditionally worn by cardinals of the Catholic church. The heads of the males also are covered in red feathers, with black masks surrounding now coral-red beaks. read more