photograph of Allen's Hummingbird by Rohan Kamath
|Some species of birds do not form pair bonds; but instead consort only briefly -- for minutes or hours. The male's investment in offspring is limited to sperm, and the female raises the young alone. Male hummingbirds, for instance, court females for a short time, mate, and then resume their quest for other females. Males of many grouse species and some shorebirds display on leks (mating grounds used each year) to attract females that depart immediately after mating. The males may subsequently mate with additional females. Such mating systems, in which no pair bond is formed, are termed promiscuous. Presumably promiscuous mating systems can evolve only where the advantage of the male remaining with the female to help in raising the young is negligible.|
Copyright ® 1988 by Paul R. Ehrlich, David S. Dobkin, and Darryl Wheye.