Table 1. _Taxonomic distribution of marine birds breeding along the Pacific Coast of Washington, British Columbia, and southeastern Alaska._
------------------------------------------------------------------------ Regions --------------------------------------- British Southeastern Total Family Common name Washington Columbia Alaska forms ------------------------------------------------------------------------ Hydrobatidae Storm-petrels 2 2 2 2 Phalacrocoracidae Cormorants 3 3 1 3 Haematopodidae Oystercatchers 1 1 1 1 Laridae Gulls and terns 2 2 3 4 Alcidae Auks, murres, puffins 6 7 9 9 Total 14 15 16 19 ------------------------------------------------------------------------
There are 19 species of seabirds that breed along the Pacific coast of southeastern Alaska, British Columbia, and Washington (Table 1). Southeastern Alaska has the largest number (17) of species. Errors in species identification are most likely with the Larus gulls, particularly in southeastern Alaska where the herring gull _(L. argentatus)_ and glaucous-winged gull _(L. glaucescens)_ breed in mixed colonies (Patten and Weisbrod 1974). A similar situation exists in Washington where the western _(L. occidentalis)_ and glaucous-winged gulls intergrade (Scott 1971). Brandt's _(Phalacrocorax penicillatus)_ and double-crested cormorants _(P. auritus)_ are often difficult to identify from the air. This would be a problem in Washington and the southwest coast of Vancouver Island, where the two species are locally sympatric.
The area under consideration is the 400-km-long Alexander Archipelago (Fig. 1). This complex pattern of islands, bays, and inlets is characterized by extremely high precipitation and typical cool marine temperatures. Average annual precipitation in the Sitka area is 245.4 cm (1931-60), and the average annual temperature is 6.3°C (U.S. Weather Bureau 1974). As a consequence of this cool, humid environment, most of the islands are densely covered with conifers, chiefly Sitka spruce _(Picea sitkensis)_ and hemlock _(Tsuga heterophylla)_, and an almost impenetrable shrub cover composed of salmonberry _(Rubus spectabilis)_, elderberry _(Sambucus callicaipa)_, devil's club _(Echinopanax horridus)_, and three species of _Vaccinium_ (Heath 1915).