The Great Blue Heron, the largest heron of North America, is widely
distributed in Canada but the estimated 1500 pairs of coastal
British Columbia Great Blue Heron are distinct from herons
elsewhere in Canada. The coastal birds are non-migratory and
remain isolated year round from heron populations that migrate.
This isolation has led to adaptations with among other features
a darker plumage and subspecies classification, Ardea herodias fannini.

Evidence based on the Canadian Wildlife Service’s Breeding Bird Surveys (BBS)
conducted between 1969 and 2000 indicates that the Great Blue Herons of
the coast of British Columbia (includes Queen Charlotte Islands and
Vancouver Island) are declining at a rate of 9.4 per cent per year.