Male-biased sex ratios in waterfowl may contribute to sexual selection and permit females to be the deciding sex in mate selection. Male characteristics potentially influencing female choice include male age, size, plumage quality, and body condition (i.e., relative body mass, fat content, or protein content). By examining characteristics of prenesting male cinammon teal (Anas cyanoptera) relative to their pair status we evaluated the predictions that (i) paired males are older and physically superior to unpaired males and (ii) older and physically superior males pair in advance of other males. Diets of paired and unpaired males were similar, as were body size, ingesta-free body mass, fat, breast, and leg muscle protein contents, and testis, liver, and plumage masses. Likewise, pair status was not associated with male age. Body protein content and percentage of alternate plumage were generally greater in paired than unpaired males, but for some unpaired individuals these values were higher than the mean values for paired males. Thus, we found only limited evidence to support the above hypotheses. Our data suggest a possible link between winter nutrition and male participation in reproduction. That is, characteristics which enable males, during winter, to acquire nutrients for initiating and completing the prealternate molt in advance of other males also may be associated with ability to obtain a mate.
