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Location Canada, Québec
Central coordinates 61o 8.99' West  47o 50.54' North
IBA criteria A4ii, A4iii
Area 1,200 ha
Altitude 0 - 30m
Year of IBA assessment 2008

Bird Studies Canada/Nature Canada

Site description The Rocher aux Oiseaux and the associated Rocher aux Margaulx are located about 32 km northeast of the Magdalen Islands archipelago. These sandstone rocks (about 1 km apart) emerge from the sea at the edge of the Laurentian channel, which is located in the middle of the Gulf of St. Lawrence. The Rocher aux Oiseaux is a flat topped island with 30 m high rock cliffs on nearly all sides. A lighthouse (now automated) and three associated buildings are located on the plateau. About 70% of the area is covered by herbs, and the remainder is bare rock. The Rocher aux Margaulx was broken into two parts more than a century ago, and is gradually be worn away by the sea. Only a small plateau remains. A third island, which was documented in Jacques Cartier?s 1534 voyage to Canada, has been completely eroded away. The Rocher aux Oiseaux and Rocher aux Margaux can be reached by helicopter or boat from the Grosse-Île sea-harbour, but access is restricted.

Key Biodiversity The Rocher aux Oiseaux and Rocher aux Margaulx support one of the six Northern Gannet Colonies in North America. In 1994, the colony was estimated to contain 9,868 pairs. This is about a 20% increase from the 1989 survey when 7,640 pairs was estimated, and almost a 50% increase from the 1984 survey when 6,590 pairs were recorded. In 1989, this colony supported about 17% of the estimated North American Northern Gannet population. Like other colonies in the Gulf of St. Lawrence, this colony has been increasing at a rate of 3 to 4% per year. In addition to Northern Gannets, a number of other seabirds nest on these islands including: Black-legged Kittiwakes (3,701 pairs in 1989 which represents over 1% of the estimated Western Atlantic population); Razorbills (about 500 birds in 1987); Common Murre (about 500 birds in 1989); Thick-billed Murres (as many as 500-1000 birds in the early 1970s, but more recently less than 100 birds); and Atlantic Puffins (about 100 birds in 1989). Moreover, it would be probable to find a few nesting Black Guillemots, Herring and Great Black-backed Gulls, and Leach’s Storm-Petrels.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Northern Gannet Morus bassanus unknown  1994  50,000 individuals  A4ii  Least Concern 
A4iii Species group - seabirds unknown  1994  20,000-49,999 individuals  unknown  A4iii   

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Rocher aux Oiseaux (Grosse-Ile) Faunal Habitat 3 protected area contained by site 4  
Rochers-aux-Oiseaux, des Migratory Bird Sanctuary 625 protected area contained by site 670  


IUCN habitat Habitat detail Extent (% of site)
Grassland Steppe & dry calcareous grassland  -
Coastline Sea cliffs and rocky shores  -

Land use

Land-use Extent (% of site)
nature conservation and research major
urban/industrial/transport major

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Les rochers aux Oiseaux. Downloaded from on 26/10/2016

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