Male fairy-wrens produce and maintain vibrant breeding colours irrespective of individual quality

Conspicuous colours may signal individual quality if high-quality individuals produce more elaborate colours or have a greater capacity to invest in colour maintenance. We investigate these hypotheses using repeated within-individual observations and experimentally-induced colour production in a wild bird, the superb fairy-wren (Malurus cyaneus). Male superb fairy-wrens undergo an annual moult from brown, non-breeding plumage to an ultraviolet-blue and black breeding plumage. Colour maintenance is especially relevant for this species because structural, ultraviolet-blue plumage colours are particularly susceptible to fading. Further, only the most sexually attractive males moult to breeding plumage early (before spring) and thereby keep their colours for an extended time before the breeding season. Our results show that (i) sexually attractive, early-moulting males do not have higher quality breeding colours and (ii) breeding colours are not impacted by experimentally inducing males to ...