| 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 |
| a 2000 km genetic wake yields evidence for northern glacial refugia and hybrid zone movement in a pair of songbirds. | hybrid zones are natural experiments that expose the forces maintaining species differences. but for cases where a trait of one of the hybridizing pair appears shifted into the range of the other, the underlying mechanism can be difficult to infer. for example, hybridization between hermit warbler (dendroica occidentalis) and townsend's warbler (dendroica townsendi) is restricted to narrow hybrid zones in washington and oregon, yet hermit mtdna can be found in phenotypically pure townsend's popu ... | 2009 | 18986973 |
| plumage and mitochondrial dna haplotype variation across a moving hybrid zone. | we analyze variation in phenotypes and mitochondrial dna (mtdna) haplotypes over the breeding ranges of hermit and townsend's warblers and across two of their three hybrid zones. within these two hybrid zones, we demonstrate that the placement, shape, and width of transitions in seven plumage characters are remarkably similar, suggesting that a balance between dispersal and sexual selection keeps these hybrid zones narrow. a consistent asymmetry in these character transition curves suggests that ... | 2001 | 11308096 |