Where do thrushes migrating to France come from? Within-France distribution and temporal changes over 70 years

Knowledge of the origin and spatial distribution of migratory bird contingents is essential information for the study and conservation of their populations. In short-distance migratory birds, their propensity to migrate has reduced over the past decades: more individuals remain year-round on the breeding grounds, and those that migrate winter at closer distance. To inform the management of these migratory populations and species subject to intensive hunting during the non-breeding season, we must document and understand how their migratory behaviours have changed over the past decades. Using ringing-recovery data spanning over the past 70 years (1950–2018), we updated knowledge on origins and within-France spatial distribution of five hunted European turdids migrating to/through France (common blackbird, fieldfare, song thrush, redwing and mistle thrush), and documented how these aspects have changed over time. Our results confirm that France hosts non-breeding birds from all Continental Europe. Partial and short-distance migratory populations from blackbird mainly come from western and central Europe and are strongly segregated in autumn and winter in France according to their origin. Surprisingly, our results relativize the presence of populations originating from Fennoscandia for the northernmost species (redwing and fieldfare), which present a slightly marked segregation. Finally, this study highlighted temporal changes in the migratory propensity for song thrush and mistle thrush, and modifications of the within-France spatial distribution for fieldfare, song thrush, and redwing. Through this new knowledge, we hope to provide a replicable method to characterize migratory populations’ distribution and bring elements to promote the differentiated management of hunted thrushes in Europe