Remarkably similar migration patterns between different
red-backed shrike populations suggest that migration rather than
breeding area phenology determines the annual cycle (2020)

Pedersen, L., et al.

The regular fluctuation of resources across the Globe guides movements of migratory animals. To ensure sufficient reproductive output and maintain viable population sizes, migratory animals should match arrival at breeding areas with local peaks in resource availability. It is generally assumed that breeding phenology dictates the timing of the annual cycle, but this is poorly studied. Here, we use light-level geolocator tracking data to compare the annual spatiotemporal migration patterns of a longdistance migratory songbird, the red-backed shrike, Lanius collurio, breeding at widely
different latitudes within Europe.