Spatial Heterogeneity in Resource Distribution Promotes Facultative Sociality in Two Trans-Saharan Migratory Birds
Figure 1
Cattle abundance a) (measured as percentage of positive contacts with cattle during road counts) and herd size b) in the summering (Europe; white) and wintering (Africa; grey) grounds of two trans-Saharan migrant species.
Box plots of cattle sizes represent median values (horizontal line marks), the central 50% of the data (boxes), the range (whiskers) and outliers (dots).