Temporal Not Foraging Factors Affect Reproductive Success for American Oystercatchers (Haematopus palliatus) on Two Barrier Islands in Virginia, U.S.A.

Barrier islands in Virginia, U.S.A. support the most breeding American Oystercatchers (Haematopus palliatus) throughout their range; however reproductive success remains low. This study focused on how the food supply might influence reproductive success on two barrier islands in coastal Virginia. From 2022–2024, 821 observations were made on foraging adults and brood provisioning to assess food profitability, distances to foraging areas, diets of breeding pairs, and brood provisioning rates. Two hundred fifty-four nests were monitored, 102 of which hatched 215 chicks. Overall, foraging factors did not affect breeding success at the study site. Instead, daily nest survival was best explained by year. Interannual variation in predator and storm activity determined hatching success. In 2024, a lack of storm overwash and limited predator activity led to higher hatching success compared to 2023 and 2022 when nor'easters flooded nests and there was high nest predator activity by foxes, avian predators, and ghost crabs. Daily brood survival was best explained by age, where daily survival decreased with age. Older chicks tended to be of larger body size and hide less from predators, which likely increased their predation risk. Efforts to control predators and increase nesting habitat elevation can support American Oystercatcher reproductive success.