Ornament size influences mating success in male rock ptarmigan

Abstract

Factors influencing male mating success in a natural population of rock ptarmigan, Lagopus mutus, were examined. In the first year of study, 1984, a survey of mating patterns revealed bigamous, monogamous and bachelor males in the population. In that year, males with the largest supraorbital combs had the most mates. After males were paired in 1984, they were captured and banded with a unique sequence of coloured leg bands for future identification. The following year, returning males with combcoloured bands were more successful at obtaining mates than were males with similar comb size but without these band colours. These results suggest that among rock ptarmigan, the comb is a target of sexual selection and that a novel, non-genetic trait, when similar in colour to the target, can also influence a male's mating success.