| ongoing movement of the hermit warbler x townsend's warbler hybrid zone. | movements of hybrid zones - areas of overlap and interbreeding between species - are difficult to document empirically. this is true because moving hybrid zones are expected to be rare, and because movement may proceed too slowly to be measured directly. townsend's warblers (dendroica townsendi) hybridize with hermit warblers (d. occidentalis) where their ranges overlap in washington and oregon. previous morphological, behavioral, and genetic studies of this hybrid zone suggest that it has been ... | 2010 | 21152406 |