Figure 1. Phenotypic and genetic makeup of the hybrid Italian sparrow.

Coloration of the map denotes phenotypic distribution as indicated by the bird drawings to the right of the map (blue: house sparrow, turquoise: Italian-house hybrids, yellow: typical Italian sparrow, orange: Italian sparrows with plumage intermediate between typical Italian and Spanish sparrows, red: Spanish sparrow). Bird drawings indicate species-specific male plumage characteristics of the three taxa [16]. Pie charts denote mean hybrid index at sampling localities where white and black color indicate house and Spanish sparrow genetic contribution, respectively. Locations with evidence of recent gene exchange between Spanish and Italian sparrows are indicated by arrows.