1) Polygamous 
of or relating to polygyny (Morris 1992). Polygyny
• (a.) Having many styles; belonging to the order Polygynia.
Male mates with more than one female during the mating season.
Having more than one female as a mate at one time
(Gk: polloi many; gyne=woman) characterised by a sinlge male having more than one female partner. See also polyandrous.
[adj] - having more than one wife at a time
polygyny, polygynous The marriage of a man to more than two women at the same time.polygynous 1. In botany, having many pistils, styles, or stigmas; specifically belonging to the order Polygynia. 2. Having more than one wife or having several wives (or concubines); practicing, pertaining to, or involving polygyny. 3. In zoology, a reference to a male animal that has several female mates; characterized by polygyny, as a species.
Describe birds group which males and females have more than one mate.
adjective having more than one wife at a time
One male mates with more than one female. 
having more than one wife at the same time; polygynous marriages are allowed by tradition in many African societies.