Bird Polygamy and Polyandry Mating - Page 1

Polygamy occurs in two forms in bird societies: polygyny (a male with several female mates) and polyandry (a female with several male mates). Polygyny is much more common than polyandry. Among backyard birds, three masters of polygyny are Red-winged Blackbirds, House Wrens, and Eastern Meadowlarks. Males of each of these species may have several female mates during the same breeding season.

The male Red-winged Blackbird achieves its polygyny by impressing first one female, then another. At any one moment it may have several females nesting on its territory, all in different stages of breeding. One may be just beginning, the second well into incubation of eggs, and the third busy feeding the young. This scheduling of the females allows the male to devote different levels of effort to the various females on his territory, thereby not spreading himself too thinly.