Bird Promiscuity Mating
A few species of North American birds are best called promiscuous. This term describes a rather chaotic social structure in which a female may mate with many males or a male with many females. Promiscuous mating may appear to be a combination of polygyny and polyandry, but polygynous and polyandrous birds make some commitment, however brief, to their mates. The Polygynous Red-winged Blackbird, for example, actually helps care for its young; the polyandrous Spotted Sandpiper defends a territory upon which the males nest. Promiscuous birds form no lasting associations whatsoever.
All of North America's hummingbirds are promiscuous breeders. The males defend large territories around important sources of food and then display to females coming to feed. Females may fly well beyond the territories of local males to find males with which to mate. The male will almost certainly never see its offspring or the nest, and most likely will not see the female for the one brief visit. But what energy he displays to each and every female who comes to call!
Left: This Pectoral sandpiper forms loose promiscuous pair-bond with its mate. Care of the eggs and young is left strictly to the females, the males migrating south before the eggs hatch.