Migration and reproduction are two of the most demanding events in a bird’s annual cycle, usually separated into different times of the year. However, a study by University of Rhode Island researchers has found that the American woodcock, a migratory shorebird, overlaps periods of migration and reproduction, a rare breeding strategy known as “itinerant breeding.” This work, published in the Proceedings of the Royal Society B, provides direct evidence of this unique strategy, shedding light on the species’ behavioral patterns. The American woodcock is known for its long bill, elaborate mating dance, and declining populations over the past half century.
The study involved tracking more than 350 female woodcocks with GPS transmitters across their flyway from the southern U.S. into Canada. The research team, led by URI Ph.D. student Colby Slezak, analyzed the tracking data and collaborated with biologists across the East Coast to verify nesting locations. This collaboration allowed for the confirmation of itinerant breeding in American woodcock, giving researchers detailed insights into this rare breeding strategy. The initiative was part of the University of Maine’s Eastern Woodcock Migration Research Cooperative, highlighting the importance of collaborative efforts in studying bird migration and behavior.
The study revealed that more than 80% of the tagged female woodcocks nested multiple times during migration, with some nesting up to six times. Females traveled significant distances between nests during northward migration, indicating a unique pattern of nesting behavior. The research team verified 26 nests from 22 females on the ground, providing concrete evidence of the species’ itinerant breeding strategy. Female woodcocks were found to nest in the south early, migrate northward, and nest again along the way, providing breeding opportunities for males during migration.
While migration and reproduction are energetically expensive tasks for birds, American woodcocks have evolved strategies to reduce these costs. They have shorter migration distances, use various habitats, and have lower reproductive costs compared to other species. The study also suggests that predation events play a role in triggering post-nesting migratory movements in woodcocks. The species often nests near open fields, increasing their exposure to predators, leading to potential nest abandonment and subsequent northward migration.
Despite declining populations and habitat loss, the study offers hope for woodcocks and other itinerant bird species facing environmental challenges. Itinerant breeders like woodcocks may have higher flexibility in adapting to environmental changes due to their willingness to breed in diverse habitats. As long as suitable habitat remains available, these species may be better equipped to cope with ongoing human development and climate change. The study provides valuable insights into the behavioral ecology of American woodcock and highlights the importance of understanding unique breeding strategies in migratory birds.
