Mating behavior When marked birds were present in a group,15-minute focal sampling (Altman, 1974) was used to record mating behaviour. We recorded data on proximity between males and females. In this regard we considered the focal male as at the centre of a circle and we repeatedly recorded the position of females, and other
males, in hypothetical circles of 0.5, 1, 2, 5, 10 and 20 m radius respectively. Proximity was here used as a proxy for male access to females as copulation is rarely observed in the wild due to their short duration