Integrating stable isotopes, parasite and ring-reencounter data to quantify migratory connectivity - a case study with Barn Swallows breeding in Switzerland, Germany, Sweden and Finland

Ecosystems around the world are connected by seasonal migration. The migrant animals themselves are influenced by migratory connectivity through effects on the individual and the population level. Measuring migratory connectivity is notoriously difficult due to the simple requirement of data conveying information about the non-breeding distribution of many individuals from several breeding populations. Explicit integration of data derived from different methods increases the precision and the reliability of parameter estimates.

We combine ring-reencounter, stable isotope and blood parasite data of Barn Swallows Hirundo rustica in a single integrated model to estimate migratory connectivity for three large scale breeding populations across a latitudinal gradient from Central Europe and Scandinavia. To this end, we integrated a non-Markovian multi-state mark-recovery model for the ring-reencounter data with normal and binomial mixture models for the stable isotope and parasite data.

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