Figure 3
From: No evidence for assortative mating within a willow warbler migratory divide
Male–female trait comparison for all pairs (n = 40). A δ15N values; dashed lines at 7‰ and 9‰ represented cut-offs for birds likely wintering in West Africa and East to South Africa, respectively; B plumage colour scores; C PC1 for body size; and D genetic ancestry to the northern subspecies. Pair counts for colour and genetic ancestry (values rounded to 2 significant digits) were represented by the size of the circle.