Figure 4.

The expected species richness of (a,b) forest birds and (c,d) grassland birds. Breeding season (a, c); wintering season (b, d). We used the best spatial models to derive these results. We excluded regions where the values of explanatory variables from the models were not within the analysis range (i.e., annual mean temperature <2°C in forests, annual mean temperature <5°C in grasslands, elevation >1,600 m, snow depth > 2.4 m). Coordinates: 30°59′–45°31′N; 129°33′–145°49′E