Dispersal, return rates and phenology in an isolated and fragmented population of a declining farmland passerine

Habitat fragmentation can contribute to population declines in farmland birds when increased isolation between sub-populations limits local connectivity, re-colonization of abandoned habitat and between-year recruitment. To check for such signatures of fragmentation in mobile grassland inhabitants, we studied natal and breeding dispersal, adult and yearling return rates, and local phenology of the fragmented and severely declining Northern Black Forest (Germany) population of the Meadow Pipit <i>Anthus pratensis</i>. We colour-ringed 153 adults and nestlings, representing almost the entire local breeding population in 2020–2022, then estimated movements and return rates based on 2041 re-sightings at 13 grassland patches. Return rates were 52% for adults and 21% for yearlings. Adults arrived earlier than yearlings and showed greater site fidelity. Natal philopatry was low, with yearlings driving the resettlement of abandoned grassland patches. Post-breeding yearling dispersal exceeded that of adults by 4.2 km, on average, with foraging sites up to 18 km from natal patches. Despite spatial fragmentation of suitable grassland habitats, the Meadow Pipit population remained well-connected, and adult and yearling return rates matched those reported from larger and, presumably, more stable populations in the species’ core range. Our data were thus not consistent with a prime role of population fragmentation or non-breeding survival for the local population decline, but strengthen earlier indications of insufficient local productivity. This emphasizes the need for further restoration of high-quality breeding habitat.