Major Brown Rock lies on the western reaches of a group of islands, within the mouth of Rivers Inlet, on the mainland coast of British Columbia. Much of the islet is a low, bare rock with a sandy beach-like enclave in the interior. The higher northwest side is vegetated with various grasses and forbes (including Elymus, Heracleum, Conioselium and Mimulus) and a pocket of salmonberry and currant shrubs. The surrounding marine area is of importance for foraging birds. Major Brown Rock is about ten kilometres northeast of Dugout Rocks in the Smith Sound Islets IBA.
Major Brown Rock is a site of national significance with 319 pairs (over 1% of the national population) of Glaucous-winged Gulls recorded nesting there during surveys in 1988. Larger numbers of non-breeding gulls roost there as well. Several pairs of nesting Black Oystercatchers breed on the islet, but not in nationally significant numbers. In some years, small numbers of Pelagic Cormorants nest on the rock and it is likely that Pigeon Guillemots nest there as well.
Several species of shorebirds (eg. Western, Least, and Spotted Sandpipers, Surfbirds, and Black Turnstones) occur there in small numbers, with occasional sightings of more than hundred recorded during the infrequent summer surveys. Of note was a flock of 450 Black Turnstones during a survey in 1977. In addition to the shorebirds and gulls, Harlequin ducks frequent the shoreline areas.
BirdLife International (2020) Important Bird Areas factsheet: Major Brown Rock. Downloaded from http://www.birdlife.org on 03/12/2020.