showed that female western gulls (Larus occidentalis) who mounted each other within the context of same-sex pair-bonds did not behave like males in terms of other aspects of their sexual behaviour. For example, the partners did not court each other in a male-typical manner with head tossing and courtship feeding. It is uncertain, however, whether female–female pair-bonds in these gulls reflect an actual preference for same-sex partners, or simply an inability to obtain male mates.