Figure 1: (a) Primary breeding distributions and allopatric sampling localities of Passerina amoena and Passerina cyanea. Area outlined by the black box is enlarged in (b). (b) Sympatric and parapatric sampling localities analyzed in this study. Background shading represents elevation and white box indicates approximate location of the sympatric contact zone. See Table 1 for more detailed information on sampling localities. Digital maps for each species [31] were downloaded from NatureServe [32] and modified.