Data from: Brood size matching: a novel perspective on predator dilution ...

A primary benefit of grouping is diluting the individual risk of attack by predators. However, the fact that groups are formed not always by solitary adults but also by subgroups (e.g., families) has been overlooked. The subgroup-specific benefit of predator dilution depends on its relative contribu...

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Bibliographic Details
Main Authors: Jaatinen, Kim, Öst, Markus
Format: Dataset
Language:English
Published: Dryad 2012
Subjects:
Online Access:https://dx.doi.org/10.5061/dryad.mn11k
https://datadryad.org/stash/dataset/doi:10.5061/dryad.mn11k
Description
Summary:A primary benefit of grouping is diluting the individual risk of attack by predators. However, the fact that groups are formed not always by solitary adults but also by subgroups (e.g., families) has been overlooked. The subgroup-specific benefit of predator dilution depends on its relative contribution to total group size. Therefore, the willingness of a subgroup to merge with others should increase the less it contributes to total group size, but the conflicting preferences of partners may result in the preferential merger of similar-sized subgroups. Here, we evaluate how the proportional contribution of subgroups to diluting risk affects group formation. We generate predictions using a bidding game over parental care and test them using data on common eiders (Somateria mollissima), in which females with variable-sized broods may form brood-rearing coalitions. The predictions (1) that size-matched subgroups should have a higher propensity to merge, (2) that predation should increase group formation ... : EiderField data on eider group formation behaviour. ...