Seabirds exhibit considerable variation in demographic parameters within a typical K-selected framework. Identification of the most sensitive of these parameters for population change is crucial for successful management and conservation. When adult survival is high and stable in seabird populations, bottom-up forces prevail and reproductive success and subsequent recruitment of juveniles will govern population dynamics. Recruitment is difficult to study, requiring large samples from throughout a metapopulation. The Atlantic puffin (Fratercula arctica) colony on Machias Seal Island is the largest in the Gulf of Maine population, and is ideally suited to explore recruitment in this species since the entire metapopulation is monitored. I first assessed trends in hatch-year parameters since the 1980s and studied whether hatch year conditions for Atlantic puffins affected the probability of natal recruitment. Despite significant declines in hatch-year parameters (wing growth, fledging body condition, quality food delivered to chicks, fledge date), none had a statistically significant effect on the probability of natal recruitment. The number of islands visited between fledging and recruiting was the only parameter with a statistically significant effect on natal recruitment. Puffins are less likely to recruit to their natal island the more islands they visit between fledging and recruitment age. I conclude that conditions experienced between fledge and recruitment may be more important in the process of natal recruitment than conditions experienced by chicks on their natal colony. These findings highlight the importance of multi-year, multi-site metapopulation-level studies when tracking changes in seabird dynamics.
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