Fig. 5

Example of a probability raster for one step of the simulation experiment for the geomagnetic navigational strategy ‘Map-constant heading’. The highest probability values are shown red (indicating higher probability of movement steps in that location) and lower probability values are yellow (indicating a lower probability of movement step in that location). These rasters were calculated before each step of the simulated trajectory and are dependent on the current position of the simulated bird and the current condition of the geomagnetic field -the green dot is the location of the minimum value of the raster. The true migratory trajectory of animal 1, interpolated to 1 h frequency, is represented by black dots. The blue line represents a straight line between the current position of the simulated trajectory at the start of the migration and the final point of the GPS trajectory. We used the geomagnetic field value intensity in this example plot