Pairing Decisions in the Harlequin Duck: Costs and Benefits

Abstract

Abstract In waterfowl, the male costs and female benefits hypothesis considers that the timing of pairing will depend on the balance between the costs and benefits for each sex. Females may benefit by increasing their access to food and social status, and by decreasing harassment from conspecifics, while maintaining a pair bond for a long period should be costly to males. To investigate costs and benefits of early pairing in the Harlequin Duck (Histrionicus histrionicus), we compared time budgets and frequency of interactions (agonistic, courtship, and mate guarding behavior) from paired and unpaired males and females. A total of 400 thirty-minute focal-animal sampling sessions were used for the analysis. Overall, feeding time did not differ between paired and unpaired birds of both sexes. However, regardless of their reproductive status, females spent about 15% more time feeding than males throughout the winter. While diving, paired males spent 4% less time underwater than unpaired males, but no differen...