van Rhijn J., Jukema J. & Piersma T. (2014) Diversity of nuptial plumages in male Ruffs Philomachus pugnax. ARDEA 102 (1): 5-20

Nuptial ornament diversity was studied in 1814 individual male Ruffs that were caught in their spring staging areas in Friesland, The Netherlands. Ornaments (hereafter called plumages) comprised of a ruff, two head tufts and facial wattles. Individual feathers were found to be plain (white, black or one hue), or patterned with black and only one hue. Patterns of feathers varied modestly within males, and greatly between males. The colour of a male’s ruff plus head tufts consisted of black and/or white and/or only one other hue. Ruff, head tufts and facial wattles differed in coloration and pattern between individuals. Using seven criteria we counted 801 different plumage variants. Nevertheless, except for wattle colour, characteristics did not combine at random. Some combinations of characteristics, such as a white ruff with white head tufts, occurred much more often than expected by chance. Other combinations, such as a white ruff with black head tufts, a black ruff with white head tufts, and a regular ruff pattern with an irregular pattern, were rare. Mostly there was conformity between ruff and head tufts: they were identical or had reversed primary and secondary colours. Nuptial plumage characteristics were only weakly associated with body size. Some associations between nuptial plumage and the timing of moult were remarkable: only white males and males with a plain ruff pattern tended to have completed moult by the time of their capture in April. We discuss our findings, including the extreme diversity of nuptial plumages among individuals, in the light of development, genetics and function.