Investigation of male Golden-winged Warbler plumage traits as sexually selected ornaments

Substantial evidence has now demonstrated that fertilization competition selects for the most effective status-signaling and female-stimulating ornaments and that females measurably benefit from choosing males with the most elaborate ornaments. Studying sexually selected traits begins with characterizing ornaments and identifying signaling functions. In this study, I characterized ornamentation of the carotenoid-based crown plumage, melanin-based throat plumage, and structurally derived tail white plumage of breeding male Golden-winged Warblers in the Appalachian Mountains. I tested for geographic and age-based variation of plumage traits and investigated their quality indicating and behavioral signaling functions. I found a latitudinal gradient of variation in crown and throat coloration and regional differences in body condition, with the southern birds showing less ornamentation and lower body condition. Plumage traits were not indicative of body condition but older birds displayed more white on their tails and co-variation of crown and throat coloration. Males with less-ornamented crowns were more aggressive to simulated territorial intrusions while males with greater tail white ornamentation provisioned nestlings more often. My study has demonstrated that there is measurable variation and signaling potential in male Golden-winged Warbler plumage traits, thus suggesting these ornaments are sexually selected traits.