Barn swallows (Hirundo rustica) are semi-colonial, migratory songbirds. They are incredibly acrobatic flyers, well-adapted to a life spent feeding on aerial insects. They are distributed across the Holarctic (a region covering most of the Northern Hemisphere) and are currently divided into 6 subspecies, shown at right. The widely distributed H. r. rustica subspecies, found throughout Europe and parts of western Asia, has been a classic model for studies of sexual selection. From work done by Anders Møller and others, it is clear that females of this subspecies prefer males with longer tail feathers (streamers) . Thus, female preference has resulted in this subspecies having the longest tail feathers of all barn swallows. However, recent work in other subspecies demonstrates interesting variation in the targets of sexual selection. Females from North America (H. r. erythrogaster) prefer darker breasted males , and show no preference for streamers.
In Israel (H. r. transitiva), females select for both color and streamer length , while in Japan (H. r. gutturalis), there is evidence of selection for throat color, without selection for tail streamer length . Determining the reasons for this variation in female preference is an ongoing goal of work in the Safran Lab. In addition, I am interested in how vocal divergence accompanies morphological changes among subspecies, as well as understanding relationships between visual and acoustic signals at individual and population levels. For example, can populations evolve dark plumage, long streamers, and complex song at the same time, or is there a trade-off in elaboration in one or more of these traits? More details on my studies are in the Research link at left.