FEMALE PIED FLYCATCHERS PREFER BRIGHTLY COLORED MALES

In birds, it has proved difficult to demonstrate conclusively that females prefer particular male traits. One problem is that females may sample few males before settling. To circumvent this problem, the mate sampling behaviour of female pied flycatchers, Ficedula hypoleuca, was followed in the field by using video-cameras, and the plumage colours of the accepted and the rejected males were compared. Females mated preferentially with the more brightly coloured males. In territorial species, another problem in the study of mate choice has been to separate the effect of female choice on the male trait from the effects of territorial quality and other male characteristics, since they will often be intercorrelated. In aviary experiments, the effect of territory quality was controlled for by giving females a mating option between a bright and a dull male, each occupying a nestbox in compartments of the same size. In one experiment, females could choose between males with natural plumage colours (bright versus dull). In another experiment, the effects of age and behavioural correlates of male plumage colour were controlled for by painting one of two dull males bright black. In both these aviary experiments, females preferred the more brightly coloured male. This shows that male plumage colour per se represents a cue for mate choice by female pied flycatchers.