Evidence for a link between plumage color and social network

In cooperative breeding species, competition for breeding space is high, and ornamentation is an important signal. In Florida Scrub-Jays (Aphelocoma coerulescens), juvenile plumage predicts dominance and condition but not adult reproductive fitness, likely because feather color varies across molts. Interestingly, adult color does not predict reproductive fitness, but change in color across molts in females predicts breeding space acquisition. We propose that sex-specific differences in modes of territory acquisition may drive differences in social network and plumage. We collected social network and plumage data for two annual cohorts of jays to examine the correlation between social network and ornamentation. We measured juvenile and adult plumage color for two annual cohorts of jays, and calculated relative change in color within individuals. Social networks were estimated with a combination of systematic and incidental aggregation sampling from February through April 2015-2016. We used the ‘igraph’ package in R to estimate social network. No significant differences in social network existed between males and females; however, females appear to have slightly larger networks and greater betweenness. More ornamented females that increased ornamentation across molts had larger networks and associated with larger cliques. More ornamented males also had larger networks, but we found no connection between color change and social network. These results suggest a link between feather color and social network, more strongly expressed in females. Because color is linked with condition and dominance in jays, more ornamented individuals are higher quality, able to foray more widely, interact with more individuals, and acquire breeding space.