Abstractions

摘要

Many male birds sport brightly coloured feathers and other ornaments in order to woo as many females as possible. By contrast, females, which tend to focus their efforts on raising their brood, are often unarguably drab. This is because females in most avian species are left on their own to raise their young and face little competition for mates. However, in some species males and females live together in family groups that share breeding responsibilities. This means that fewer females get to mate, so they too have to compete. Dustin Rubenstein of Columbia University in New York City and Irby Lovette of the Cornell Laboratory of Ornithology in Ithaca studied 45 species of African starling to examine the evolutionary consequences of such competition (see page 786)