Mate acquisition tactics in polyandrous spotted sandpipers (Actitis macularia): the role of age and experience

We consider resource-defense polyandry and mate-access polyandry as female mating tactics in spotted sandpipers (Actitis macularia). These tactics can be distinguished by the resource females defend, female interclutch movement, expected reproductive success after moving, and male and female dispersion. We examine these characteristics relative to patterns observed in a 17-year study of spotted sandpipers, a species traditionally considered resource-defense polyandrous. On average, 26% of spotted sandpiper females each year were monogamous. Older females were more likely to be polyandrous, and polyandrous females of each age employed different mating tactics. Yearlings were typically sequentially resourcedefense polyandrous. Two-year-olds were primarily simultaneously polyandrous, exhibiting equivalent proportions of resource-defense and mate-access polyandry. Older females were primarily simultaneously resource-defense polyandrous. Females tended to stay on territories where they and/or their mates had greater breeding experience (i.e., many clutches laid for females, many clutches diat hatched for males); females that moved went to territories where their mates had a history of breeding success. Location changes between clutches by polyandrous females were better described by breeding experience on a territory than by age.