Bonaventure Island is located on the Gulf of St Lawrence approximately 3.5 km from the shore of the Gaspé Peninsula. The 416 ha island is roughly circular in shape with cliffs on the southeastern and northeastern shores rising to a height of approximately 75 m. The island lies within the Atlantic Highlands biome with balsam fir and spruce being dominant species. The cliffs and shorelines are generally devoid of vegetation with the exception of some arctic / alpine species that are able to withstand the harsh microclimate. Thus far, 572 vascular plant species have been recorded on the island, including eight that are rare in the province of Quebec and five that are provincially vulnerable or threatened.
Bonaventure Island is renowned for its Northern Gannet colony. In 1994, over 32,000 breeding pairs were observed making it the largest colony in North America. Using population estimates from the late 1980s, there may be as much as 9% of the global population and approximately 50% of the North American population present at Bonaventure Island during the breeding season.
In addition to Northern Gannets, equally impressive numbers of Black-legged Kittiwakes and Common Murres also nest on the cliffs. In 1989, over 23,000 pairs of Black-legged Kittiwakes were recorded, representing as much as 9 to 12% of the western Atlantic population. In the same year, almost 28,000 pairs of Common Murre were recorded. This represents approximately 5% of the eastern North American Common Murre population. The island is clearly of global significance for nesting colonial seabirds.
Other seabirds nesting on the island include Double-crested Cormorant, Great Black-backed Gull, Herring Gull, Black Guillemot, Razorbill, Atlantic Puffin, and Leach's Storm-Petrel. In all, ten different seabird species nest on the island. During the summer and early fall Harlequin Ducks from the eastern population (nationally endangered) concentrate around both the island and Percé Rock. Numbers observed have been as high as 118 individuals (early September 1989).
In addition to seabirds, the island supports a typical community of boreal forest birds (Blackpoll Warbler, Boreal Chickadee etc.) and other habitat generalists in the abandoned fields. As of 1985, 218 bird species had been observed within the park.
BirdLife International (2022) Important Bird Areas factsheet: Bonaventure Island. Downloaded from http://www.birdlife.org on 18/01/2022.