Studying birds in the context of the annual cycle: Carry-over effects and seasonal interactions

Background/Question/Methods

Migratory birds spend different parts of the annual cycle in geographically disparate places. The conditions during each period are likely to affect individuals during subsequent periods. This simple fact presents us with considerable obstacles for understanding how agents of global change (i.e., climate, land-use) will influence the ecology, evolution, and conservation of migratory birds. Such inter-seasonal effects are poorly understood within most avian migration systems, in large part because it has been difficult to follow individuals and specific populations year round (i.e., migratory connectivity). This study seeks to understand how carry-over effects and seasonal interactions affect avian migration and breeding success.

Results/Conclusions

Long-term research on American Redstarts in Jamaica shows how events on wintering grounds, such as climate and habitat, affect arrival time and body condition of individual birds on breeding areas, and how these parameters determine breeding events and annual survival. Understanding how climate change will influence migratory organisms requires studying these organisms in the context of the entire annual cycle. This work can inform agencies and other organizations who manage for the conservation of migratory birds on the breeding grounds of the need to incorporate a full life cycle approach to bird conservation if management actions and expenditures are to have the desired effect.