How Do Synchrony in Survival and Productivity Influence Abundance Synchrony in European Landbirds?

Synchronous fluctuations in species' abundance are influenced by synchrony in underlying rates of productivity and survival. However, it remains unclear how rate synchrony varies in space and time, contributes to abundance synchrony, and differs among species. Using long-term annual count (number of adults captured), adult survival and productivity (number of juveniles captured per adult) data for breeding land-birds at ringing sites across Europe, we show that synchrony is strongest and largest scale in productivity and weakest and smallest scale in counts. However, counts fluctuate more synchronously with survival than they do with productivity. These patterns hold for species which do not migrate or only migrate within Europe (European-residents) and those migrating to sub-Saharan Africa (subSaharan-migrants), but the periodicity of productivity and survival synchrony is longer in European-residents than in subSaharan-migrants. This suggests that survival and productivity synchrony may interact to weaken abundance fluctuations but are influenced by environmental drivers operating over differing timescales in European-resident and subSaharan-migrant species.