Migration phenology and breeding areas of Song Thrush Turdus philomelos wintering in Italy: a four-year study with satellite transmitters

The miniaturization of individual tracking devices has greatly enhanced our ability to remotely track the migratory movements of even relatively small species (50-100 g). One such species is the song thrush (Turdus philomelos), a short-distance, intra-palearctic migratory passerine with a broad wintering range spanning all Mediterranean countries. In many of these regions, the species faces intense hunting pressure. Identifying its migration routes and phenology is therefore essential for informing management initiatives targeting this game species. Between 2021 and 2024, a total of 48 Song Thrushes were captured using mist nests between early December and January across three Italian regions: Sardinia, Marche and Puglia. They were fitted with the smallest available Argos PTT tags (2 g). From these deployments, we documented 31 pre-breeding migrations. Among 26 of these migrations with sufficient data, the mean onset of pre-breeding migration was 19 March, with the earliest departure recorded on 31 January. From 2021 to 2024, due to widespread tag failures we obtained complete migration tracks only for six individuals. Three of these migrated to breeding sites in northwestern Russia, two to central Russia, and one to Croatia. Our findings suggest that Song thrushes wintering in Italy come from a wide geographical range, spanning from eastern Europe to East Siberia, highlighting the importance of Mediterranean countries for different breeding populations. Satellite tracking is an essential tool for understanding the migration phenology and breeding sites of Song thrushes. The development of GPS-GSM devices of compatible weight could improve location accuracy and movement precision in future studies.