Frederick Island is located off the west coast of Graham Island, the largest of the Queen Charlotte Islands, between Langara Island to the north and Hippa Island to the south. The perimeter of the island is rocky. On its north, west, and south sides abrupt knolls give way to a more uniform slope rising to the higher areas of the island. Most of the knoll and perimeter slopes are vegetated with a predominantly sitka spruce forest and a grassy understory. Further from shore the vegetation changes to one of mixed western hemlock, western red cedar, and sitka spruce forest with moss understory. An interior area of cedar, lodgepole pine, and sphagnum bog is located towards the northwest end of the island.
Frederick Island supports the largest seabird colony on the Queen Charlotte Islands. Globally significant breeding populations of Ancient Murrelets (136,000 breeding birds or approximately 9% of the population) and Cassin's Auklets (180,000 breeding birds or approximately 5% of the population) are present. For Ancient Murrelet, a species also listed as nationally vulnerable, Frederick Island has the largest colony of the 26 islands that have confirmed nesting records in British Columbia (the only area in Canada where this species occurs). It has the third largest Cassin's Auklet colony of the 52 island colonies in British Columbia where they are known to breed. The island also supports several pairs of Peregrine Falcons (ssp. pealei), a species considered nationally vulnerable. The surrounding marine waters are important staging areas for breeding seabirds. To the north, this zone extends to the vicinity of two small islets that are within 5 km of Frederick Island. "Grassy" and "Wooded" islets, together with Frederick Island, support nationally significant breeding populations of Black Oystercatchers (40; approximately 2.6% of the national population) and Pigeon Guillemots (145; approximately 1.4% of the national population).
BirdLife International (2020) Important Bird Areas factsheet: Frederick Island. Downloaded from http://www.birdlife.org on 27/10/2020.