Nonreproductive sexual behaviors such as pseudocopulation (also referred to as noncopulatory mounting and backstanding), homosexuality, and autoeroticism have been reported in more than 230 species of birds in at least 37 families (Bagemihl 1999, Balcombe 2006). Th functions of nonreproductive sexual behaviors in birds are poorly understood. Such behaviors, which include reverse mounting during the breeding season (e.g., Nuechterlein and Storer 1989) and pseudocopulation outside of the breeding season (e.g., Short 1971), are oftn associated with courtship or pair bonding. Reverse mounting and pseudocopulation may also occur in social contexts outside of the pair bond, perhaps to maintain group dynamics by reducing aggression (e.g., MacRoberts and MacRoberts 1976, Moynihan 1990, Dawson and Mannan 1991, Hagemeyer 2016).