Effect of habitat and resource use on reproductive success of Eurasian Oystercatchers Haematopus ostralegus breeding in Iceland

The reproductive success of breeding birds is influenced by many factors, including the habitat they select for breeding. Eurasian Oystercatchers Haematopus ostralegus breeding in Iceland provide a valuable opportunity to study the potential effects of differences in habitat and environmental quality on reproductive success. Oystercatchers breed in both coastal and terrestrial habitats and hatch semi-precocial chicks reliant on parental feeding. We compared the reproductive success of Oystercatchers breeding in different habitats in Iceland. In addition, we obtained provisioning data for the northwest population, in which pairs delivered both coastal and terrestrial prey to their chicks, as a measure of resource use. The results show that reproductive success varied with both habitat and region and was higher in regions of predominantly coastal habitat use. Variation in predation rates and resource availability are likely driving these differences. Adults provisioned more items during low and mid tides and with increasing chick age, and the rate of items provisioned varied with prey type and size, likely reflecting the most profitable food items. Iceland is a globally significant breeding area for Oystercatchers and other migratory waders. Understanding how species utilize different habitats and resources, and how that might be translated into breeding success, is necessary to effectively contribute to the management of important bird areas.