Why are male birds more brightly colored than females?

This is not true for all bird species, but it is true for many birds we find in North America, such as the cardinal. The male cardinal is brilliant red, with a red crest and a striking black face. The female is a dull, gray-brown imitation. The reason? Males birds need to be conspicuous in order to attract a mate's attention, and to defend a breeding territory from competing males. Females, on the other hand, are inconspicuous, which helps to protect them from the sight of predators and competitors during the nesting process. A brightly colored female cardinal would be easily spotted by a hungry hawk or owl. But in her drab attire, she blends well with the viney tangles and brambles in which cardinals prefer to nest.  more