Seasonal connectivity in settlement decision of migratory birds

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In migratory bird species, the ability of individuals to settle on good quality winter and breeding habitat can determine their survival and reproductive success. Recent evidence shows that in migratory systems, some individuals can occupy the best sites at both ends of the range. This connectivity has considerable consequences for demography, life histories and conservation. In many migratory birds, parents migrate independently of their offspring, so juveniles must choose winter and breeding locations without any guidance. As adults tend to return to the sites they have used previously, these juvenile decisions are critical. This study will identify the mechanisms that determine juvenile settlement decisions, and their implications for population regulation, in black-tailed godwits, a migratory shorebird. Studies of migratory species are complicated by the vast distances over which individuals move. The godwit system is ideal for such studies because large numbers of marked individuals are routinely tracked throughout the range, and because chemical signatures in feathers can determine the wintering habitat of breeding birds. Understanding these settlement decisions will allow us to predict the consequences of the loss of different sites throughout the range for this species, and to identify the key parameters of importance in similar migratory species.