Data from: Broad-scale patterns of the Afro-Palearctic landbird migration

Aim: Animal migration strategies balance trade-offs between mortality and
reproduction in seasonal environments. Knowledge of broad-scale
biogeographical patterns of animal migration is important for
understanding ecological drivers of migratory behaviours. Here we present
a flyway-scale assessment of the spatial structure and seasonal dynamics
of the Afro-Palearctic bird migration system and explore how phenology of
the environment guides long-distance migration. Location: Europe and
Africa. Time period: 2009–2017. Major taxa studied: Birds. Methods: We
compiled an individual-based dataset comprising 23 passerine and
near-passerine species of 55 European breeding populations where a total
of 564 individuals were tracked migrating between Europe and sub-Saharan
Africa. In addition, we used remote sensed observations on primary
productivity (NDVI) to estimate the timing of vegetation green-up in
spring and senescence in autumn across Europe. First, we described how
individual breeding and non-breeding sites and the migratory flyways link
geographically. Second, we examined how migration timing along the two
major Afro-Palearctic flyways is tuned with vegetation phenology en route
and at the breeding sites. Results: While we found the longitudes of
individual breeding and non-breeding sites to be strongly positively
related, the latitudes of breeding and non-breeding sites were negatively
related. In autumn, timing of migration was similar along the Western and
the Eastern flyways and happened ahead of the autumnal senescence of
vegetation. In spring, migration timing was approximately two weeks later
along the Eastern flyway than on the Western flyway which coincided with
the later spring green-up in Eastern Europe. Main Conclusions: Migration
of the Afro-Palearctic landbirds follows a longitudinally parallel
leap-frog migration pattern where migrants track vegetation green-up in
spring and depart before vegetation senescence in autumn. However, the
ongoing global change have the potential to disrupt this spatiotemporal
synchronization between migration timing and spring green-up with variable
effects on different migrant populations.