JUKEMA J & PIERSMA P (2004) Small male ruffs Philomachus pugnax with feminine plumages: evidence for a third reproductive strategy, the faeder?. LIMOSA 77 (1): 1-10.

We describe the existence of small-sized male Ruffs Philomachus pugnax with a female-like breeding plumage that may represent a third reproductive strategy within the complex mating system of this enigmatic and highly sexually dimorphic shorebird species. Fourteen males with body dimensions intermediate between the males (the bigger sex) and the females were examined (12 were collected between 1984 and 2001 and dissected, of which one bird was an immature and all others in their second or subsequent calendar years, and two adult birds were brought in captivity in 2002; all birds were molecularly sexed). They were found to possess pairs of perfectly normally dimensioned testicles and were all found to represent the homogametic sex (unlike mammals, in birds these are the males). Their plumage, which gave these intermediate males a distinctly feminine appearance, contained many so-called 'striped' feathers typical of the first feather generation after the winter plumage in normal males. This feather type has been proposed to represent the original breeding plumage of less evolved forms of this sandpiper. Being quite small and so female-like, the intermediate males are of a cryptic nature, which may help them to obtain matings on the leks. We reckon that less than 1% of the males stopping over in Friesland in spring belong to this category, but suggest that a female-like habitat choice will mean that higher percentage might be found at spring stopover sites further east.
      We propose that these cryptic feminine males represent a perhaps less evolved form of maleness in Ruffs, representing (in addition to the 'resident'and 'satellite' strategies) a third male reproductive strategy that may even include parental caretaking. As a logical consequence of, but also dependent on, these suggestions, we like to propose to indicate the third category of males with the name faeder strategy, faeder being the Old-English equivalent of faar, a Frisian word meaning old- and arch-father. We were astonished to find evidence for the small feminine males in such a well-studied species, and are excited by the idea that a basic, 'less-evolved', mating strategy might have persisted over time at low frequency. We regard this as the first descriptive account upon which further investigations, and publications in the international literature, will be based. Ruff Philomachus pugnax

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