Authors: Paul Dufour et al.
Year: 2021
Publication: Current Biology
Abstract: The evolution of migration routes in birds remains poorly understood as changes in migration strategies are
rarely observed on contemporary timescales.1–3 The Richard’s Pipit Anthus richardi, a migratory songbird
breeding in Siberian grasslands and wintering in Southeast Asia, has only recently become a regular autumn
and winter visitor to western Europe. Here, we examine whether this change in occurrence merely reflects an
increase in the number of vagrants, that is, ‘‘lost’’ individuals that likely do not manage to return to their
breeding grounds, or represents a new migratory strategy.4–6 We show that Richard’s Pipits in southwestern
Europe are true migrants: the same marked individuals return to southern France in subsequent winters and
geo-localization tracking revealed that they originate from the western edge of the known breeding range.
They make an astonishing 6,000 km journey from Central Asia across Eurasia, a very unusual longitudinal
westward route among Siberian migratory birds.7,8 Climatic niche modeling using citizen-science bird data
suggests that the winter niche suitability has increased in southwestern Europe, which may have led to
increased winter survival and eventual successful return journey and reproduction of individuals that initially
reached Europe as autumn vagrants. This illustrates that vagrancy may have an underestimated role in the
emergence of new migratory routes and adaptation to global change in migratory birds.9,10 Whatever the underlying
drivers and mechanisms, it constitutes one of the few documented contemporary changes in migration
route, and the first longitudinal shift, in a long-distance migratory bird.