Multimodal sexual selection in a warbler: plumage and song are related to different fitness components

Abstract

Many species possess multiple sexual signals that are produced in different modalities. Signals from different modalities may convey different or similar (redundant) information, or be intended for different receivers. We studied sexual selection on two such signals (plumage and song) in the common yellowthroat, Geothlypis trichas. We measured the coloration and size of both a carotenoid-based and a melanin-based plumage ornament and defined singing consistency as the lack of variability between repeated renditions of the same song. Overall, we found that plumage ornaments predicted within-pair mating success, while song consistency predicted extrapair success. Only plumage was related to male condition but, among experienced males, consistent singers had higher survival rates. Singing consistency was more variable than plumage, as performance varied across observations of the same male in relation to social context and date. Our results suggest that visual and acoustic signals in this species are most important in different sexual selection contexts.