Fiery red heads: female dominance among head colour morphs in the Gouldian finch

Although the evolution of genetic color polymorphisms has received much theoretical interest, few empirical studies have investigated the adaptive function of alternative color morphs. Furthermore, most studies have focused almost exclusively on the evolution and adaptive expression of male coloration, leaving the role of conspicuous female coloration largely unknown. Using the color polymorphic Gouldian finch (Erythrura gouldiae), this study experimentally tests the status signaling function of head color (red, yellow, and black) among the 3 female color morphs. In standardized dominance contests between unfamiliar females of different head colors, red-headed females dominated both black- and yellow-headed females. During contests between the morphs, red-headed females passively displaced black- and yellow-headed opponents, whereas interactions between red-headed dyads were particularly aggressive and more frequent than interactions within dyads of the other color morphs. This effect of red dominance further persisted when head color was experimentally altered; red-manipulated females (of the other morphs) dominated both black- and yellow-headed females, whereas blackened red-headed females were dominated by naturally red-headed birds. Together with similar dominance-related differences among male morphs, these results suggest that the 3 color morphs may display alternative strategies in dominance behavior.