The fact that northern males exhibit differential recognition indicates that northern females tend not to mate with "heterospecific" males from the south; thus it is not necessary for the northern males to respond strongly to the song from a southern challenger.
O feito de que os machos do norte mostren un recoñecemento diferencial indica que as femias do norte tenden a non aparearse con machos “heteroespecíficos” do sur; así que non é preciso para os machos do norte responder fortemente á canción dun rival do sur.