Morphological Correlates of Dominance in Captive Male Red-Winged Blackbirds

Abstract

A strong, positive relationship between size and dominance was found in A. phoeniceus. Large size contributed to success in obtaining and defending territory which led to high pairing success. The advantage of large size may be responsible for evolution of larger males with size, ultimately limited by the energetic disadvantage of large size. Epaulet size, color and dominance were positively correlated in adults and 1st-yr males. These correlations disappeared if adults were considered alone. Epaulet size and color do not seem to function as dominance signals in adult males.