Figure 1.

(a) Male Resplendent Quetzal in nest hole in Costa Rica, his long tail still pointing the way it did when he entered. The long tail and bright colors of many male birds are examples of female choice, a form of sexual selection, distinct from natural selection, even though it is still “natural.” The ornaments and colors of such male birds are actually survival handicaps, and research has shown that choice of such mates by females increases their reproductive success by providing them with robust genes and the likelihood that their male offspring will also be more attractive to females. (b) Female Resplendent Quetzal in Costa Rica, with a much shorter tail than the male and less bright colors.