Observations on male-male tandems are reported; these tandems occur at very low frequency during mate guarding sequences. When initiating a tandem, a male territory resident grabs an intruding male behind the head and flies with him. This behavior is similar to the tandem formation more usually associated with male-female pairs. Because the male-male tandems occurred during mate-guarding and because tandems do not follow courtship of the intruder by the resident, this rare behavior is interpreted as a form of mate guarding rather than misdirected mating behavior.