We used population- and individual-based genetic approaches
to assess barriers to movement in black-backed woodpeckers (Picoides
arcticus), a fire-specialist that mainly occupies the boreal
forest in North America. We tested if male and female woodpeckers
exhibited the same movement patterns using both spatially implicit
and explicit genetic analyses to define population structure
and movement patterns of both sexes among populations. Three
genetic groups were identified, a large, genetically continuous
population that spans from the Rocky Mountains to Quebec, a small
isolated population in South Dakota and a separate population
in the western portion of their distribution (Oregon). Patterns
of genetic diversity suggest extensive gene flow mediated by
both males and females within the continuous boreal forest. However,
male-mediated gene flow is the main form of connectivity between
the continuously distributed group and the smaller populations
of South Dakota and Oregon that are separated by large areas
of unforested habitat, which apparently serves as a barrier to
movement of female woodpeckers.