Figure 1. Map showing the centroid coordinates of each Ortolan
Bunting singing group (black circles) which had been visited in at least
one pair of consecutive years between 2000 and 2018, so that at least
one male territory was observed (n = 238) in the first of those
surveys. Singing groups were classified into seven major regions
indicated with black line. Discarded singing groups (n = 41), not
fulfilling these criteria, are indicated by triangles.