Breeding habitat is open forested areas with conifers, mainly ponderosa pine, douglas-fir, and grand fir.

Subalpine fir and western larch may also be important components of good habitat for these birds.

They are permanent residents in some parts of their range; migrating birds form small flocks and may travel as far south as central Mexico.

This woodpecker is associated with mature larch forests in south-central British Columbia; less than 500 individuals breed in Canada.

[4] The species took its common name from Lieutenant Robert Stockton Williamson, who was the leader of a surveying expedition which collected the first male.