Hippa Island lies just north of Rennell Sound on the west coast of Graham Island. The island is heavily forested, with Sitka spruce being dominant along the shore, and western hemlock and red cedar becoming dominant away from the shoreline. Ground cover in the mature stands of forest is predominantly mosses, with grasses occurring along the shore edges and on the more open knolls, especially along the north and west sides of the island.
The western side of the island has a rugged, dissected shoreline of cliffs, knolls and recessed beaches, while the northeastern side, which faces Graham Island, has a more uniform shoreline. At the southern end, the island rises steeply to its peak, while the northern end stretches out in a low undulating peninsula. It ends with a small islet separated from the main island by a narrow channel of water.
Hippa Island is a site of global significance for Ancient Murrelets. It is also the second largest Ancient Murrelet colony in British Columbia. About 40,000 breeding pairs were documented during studies completed in1983 (about 8% of the world, and as much as 15.2% of the national population). Large numbers of Fork-tailed Storm-Petrels (about 5.7% of the national population) and Leach's Storm-Petrels (as much as 2.3% of the western Canada Population) have also been recorded. In addition, the number of Cassin's Auklets breeding on the island approaches the threshold for a site of national significance. The island also supports several pairs of Peregrine Falcons (ssp. pealei), which are listed by COSEWIC as nationally vulnerable. Other species of seabirds nesting on Hippa Island include Pelagic Cormorants, Black Oystercatchers, Glaucous-winged Gulls, Pigeon Guillemots, and Tufted Puffins. Bald Eagles also nest on both the main island and the small northern islet.
The waters surrounding Hippa Island (out to a minimum distance of 5 km and extending north to Hughes Point and south to Skelu Point) have been identified as being important to local seabirds. In particular, Hippa Passage (between the island and the west shore of Graham Island) has been identified as an important staging area for the breeding seabirds.
Conservation responses/actions for key biodiversity
Hippa Island is part of the Vladimir J. Krajina Provincial Ecological Reserve. The primary threats to the area, and the seabirds that nest there, are potential oil spills and the spread of introduced predators (raccoons and rats) from adjacent shores. The islet is also vulnerable to damage from human trampling.