Social interactions often play an important role in determining an individualâs reproductive success. To date, most research on social environment and reproductive success has focused on the breeding season social environment. But in animals that do not migrate, the non-breeding social environment may be just as important in determining which individuals express sexual signals, and when these signals are acquired. Red-backed fairy-wrens, an Australian songbird, molt into breeding plumage months to weeks prior to the beginning of the breeding season. Here we measured the effect non-breeding social environment had on timing of molt into breeding plumage and reproductive success. We collected observations of associations between individuals and their plumages in a color-banded population of red-backed fairy-wrens throughout the non-breeding season. Preliminary analyses show that age and the number of males in breeding plumage a male interacted with were important determinants of when a male acquired breeding plumage. We will report on how non-breeding social environment influenced reproductive success through its effect on timing of molt into breeding plumage.