Cactus wrens form permanent pair bonds, and the pairs defend a territory where they live year-round.[1] There is a distinctive greeting call between pair members, where they spread their wings and tails and give a harsh call.[23] The same motions are used as a breeding display, but with a non-ritualized duet call.[14] Since males and females are identical, birds recognize members of the opposite sex not by size or color but by behavioral differences.