Fig. 1

a Study area in the Kauhava region, Western Finland, consisting of a mix of mainly two contrasting habitats: homogeneous open habitat in the West and heterogeneous habitat in the East; black dots indicate kestrel nest-boxes. b Territory land cover heterogeneity (TLCH) for kestrel territories in the study area; represented as min (TLCH = 0.03), 1st quartile (TLCH = 0.18), median (TLCH = 0.49), 3rd quartile (TLCH = 0.68) and max (TLCH = 0.79) value (TLH > median shown in green, TLH < median shown in yellow), whereby smaller THL scores indicate homogenous landscapes, and higher TLH scores indicate heterogeneous landscapes. c Periodic 3-year vole cycle covering the study period 2011–2013 and showing the increase (2011), decrease (2012) and low phase (2013), based on snap-trapping data (no. of Microtus voles trapped per 100 trap-night) in spring (May) and autumn (Sep), in two sampling plots in large fields (homogenous landscapes in the West) and small fields (heterogenous landscapes in the East) respectively, of the study area