Can mixed singing facilitate coexistence of closely related nightingale species?

Abstract

Mixed singing in songbirds is usually considered to result from erroneous learning from other species, but we suggest it might be rather adaptive. Our results show that mixed singing of Thrush Nightingale males, which incorporate songs of the Common Nightingale in their repertoires in areas where both species co-occur, may help these 2 species to establish boundaries of their territories, and thus facilitate their coexistence before divergence in ecological niches evolves.