Sexy streamers? The role of natural and sexual selection in the evolution of hirundine tail streamers

Abstract

In this comment we review some experiments, which address the initial selection pressures promoting the development of tail streamers in some hirundine species. The results of recent experiments have been interpreted as providing evidence for the hypothesis that tail streamers evolved as a handicap, through sexual selection. We offer an alternative explanation with evidence from our studies which suggest that tail streamers may have evolved initially through natural selection for increased manoeuvrability, and would not therefore originally act as a handicap.