(adjective) Describes the behavior of mating with several partners during a single breeding season.
Polygamous behavior is quite widespread among birds but the degree of polygamy can vary greatly. It is much more common for males to have multiple female partners during the nesting season, though in some species females are known to have multiple male partners, even to the point of raising broods in which siblings have different fathers. Polygamy is most common in harsh nesting conditions that make it necessary for birds to use several partners to increase the chances of surviving offspring.
In a polygamous mating, the less polygamous partner, typically the female, is responsible for the majority of the care and raising of the young, from nest building to incubation to feeding. Duties may be shared, however, depending on the partner’s level of polygamy and the condition of additional mates.