APPENDIX 1. GLOSSARY OF TERMS. Key words used in this review and their meanings in the current context; references cited refer to literature from which the terms derived or were discussed, but definitions may not be identical. Carry-over (i.e., individual-level seasonal interactions) – influence of events occurring in one season on individual survival or reproduction in a subsequent season (Norris 2005) Density-dependence (i.e., population-level seasonal interactions) – population regulation based on limited resources, taking the form of negative relationships between seasonal abundance (or its drivers) and subsequent fitness; e.g., a linear negative relationship between breeding success and nonbreeding survival (Sillett and Holmes 2005, Webster and Marra 2005) Environmental-level covariation – climate-driven covariation between consecutive seasonal vital rates Migratory connectivity – links between breeding and nonbreeding populations, i.e., the degree to which individuals from the same breeding area share nonbreeding areas and vice versa (Webster et al. 2002) Nonbreeding events – changes occurring during stationary or migratory nonbreeding seasons that could have implications for the fitness of seasonal migrants, e.g., habitat alteration, direct mortality threats, reduction in resource availability, interruption of migration route Seasonal interactions – effects of events or changes in one season on survival or reproduction in another season; can occur at individual-level ,“carry-over”, or population-level ,“density dependence” (Runge and Marra 2005) Seasonal migrants – animals that make extended seasonal movements between geographically separated regions within their life cycle (e.g., Fig. 1); simply termed “migrants” in this review Sensitivity or elasticity (of a vital rate) – absolute or proportional change in population growth rate λ resulting from a change in that parameter (Caswell 2001)