COLLABORATIVE TACTICS FOR NESTSITE SELECTION BY PAIRS OF BLUE FOOTED BOOBIES
AbstractThe dual concern model suggests that pairs of animals can use four different behavioural strategies to resolve disputes that arise when making joint decisions. Based on their reproductive biology, we predicted that mated pairs of blue footed boobies would use one of these strategies, collaboration, when deciding on a location for their nest. Many of the behaviour tactics diagnostic of collaboration were observed in boobies. For instance, nestsite selection was accompanied by extensive exchanges of a specialized communication signal (nestpointing), rates of nestpointing at a given site were strongly related to the likelihood that a pair would select that site for their nest, couples in which the male and female 'disagreed' about the merits of an initial site went on to investigate additional sites together ('expanding the pie'), individuals pointed at maximal rates at a site only after their partner had already pointed at that same site ('feeling out procedures'), and both sexes appeared to have 'veto power' over potential nestsites, in the sense that a site was virtually never accepted for the nest if one of the two partners failed to point at that site prior to clutch initiation. These results support the hypothesis that mated pairs of blue footed boobies may use collaborative tactics when selecting a nestsite; descriptive accounts suggest that similar tactics may occur in other birds in which mated pairs jointly decide on the location for their nest.