Like many species, sexual selection shows up in cardinals with the males having to show off and the females getting to choose. Physically, males are a bit larger than females and they vary greatly in color. Females are a mousy brown, so that they can camouflage well in their nests, and protect their young from hawks and other predators. Males, on the other hand, are very very bright red. Their plumage doesn’t change throughout the year either but stays a bright red. Their bright feathers make them an easy to spot, so brighter males are seen as more fit because it shows they have potentially escaped being prey. However, they also do not have super high mortality rates because they do not migrate and instead stay in one place all year. Brighter males also reproduce more, have larger territories, and offer better parental care. One reason for this is that the brightness of a cardinal’s feathers are related to what he eats. If he is healthier and eating more, he will be brighter and redder. In this way, the color of his feathers is directly correlated with his fitness. Because females have chosen throughout time the redder, brighter males, they have encouraged the evolution of redder, brighter males.