Plumage colour and male-male interactions in the pied flycatcher

Abstract

Abstract. The influence of male colour on male-male interactions in the pied flycatcher, Ficedula hypoleuca, was studied using several types of field experiments. This species exhibits delayed plumage maturation, each male becoming more conspicuously black and white from the first to the second breeding summer. However, individual males vary even more, some old males being as brown as females. When territorial males were presented with a choice between brown and black male intruders (or brown males painted black) they directed more aggression towards the black males. Brown plumage did not help males obtain nestboxes close to other males. If anything browner males were at a disadvantage (though not significantly so) when establishing territories close to other mates. Nor was there any association between male colour and (1) aggressiveness towards model or live intruders, or (2) the capacity to prevent other males from occupying neighbouring nestboxes. Consequently, variation in male colour has only a slight impact on male-male interactions.