Female pied flycatchers prefer males with larger song repertoires

Abstract
The evolution of secondary sexual male characteristics such as large song repertoires and bright plumage colour in birds, has been explained by sexual selection. In male pied flycatchers, Ficedula hypoleuca, song complexity correlates with phenotypic qualities like body condition and plumage colour. Here we show experimentally that females prefer males with larger song figure repertoires and more versatile song when given the choice between a male with a smaller repertoire and less versatile song and another male with a larger repertoire and more versatile song. Other male characteristics, like plumage colour, were similar in the two males. In the aviaries, the females started nest building with the male with the more complex song. We discuss potential benefits to females of choosing males with complex song.