Rankine and Langtry Islands IBA Report

Posted March 19, 2010 | Categories : 44,Reports,Research |
IBA Rankine and Langtry Islands
Queen Charlotte Islands, British Columbia
Site Summary
BC137 Latitude
52.261° N
131.057° W
0 – 50 m
103.2 km²
coniferous forest (boreal/alpine), scrub/shrub, rocky flats & barrens
Land Use: 
Not Utilized (Natural Area)
Potential or ongoing Threats: 
Disturbance, Introduced species, Oil slicks
IBA Criteria: Globally Significant: Congregatory Species, Colonial Waterbirds/Seabird Concentrations, Nationally Significant: Congregatory Species
Conservation status: Ecological Reserve (provincial), National Park
Restricted access for IBA coordinators
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Site Description

Rankine Islands and Langtry Island lie off the mouth of Carpenter Bay near the south end of Moresby Island. Included in the IBA are the marine waters within a five km radius of the islands. Most of the vegetated areas of the larger west Rankine Island are forested with Sitka Spruce, Western Red Cedar, and Western Hemlock being dominant species. Where windfalls have occurred, areas of young re-generating spruce predominate. The smaller eastern islet has extensive bare rocky areas around the shore, with lush grass and forbs under a sparse stand of spruce that grades into thicker forest habitats. Langtry, the other island supporting nesting seabirds within this area, has a luxuriant cover of herbaceous vegetation and deciduous shrubs under an open spruce forest.


Although small in size, the islands within this site support dense breeding colonies of four seabird species: Ancient Murrelets, Cassins Auklets, Fork-tailed Storm-Petrels, and Leachs Storm-Petrels. All four species occur on Rankine Islands, while Langtry supports only Fork-tailed and Leach?s Storm-Petrels.The colony of Ancient Murrelets on west Rankine Island is the third largest colony in British Columbia. In the mid-1980s, a population of about 26,200 pairs was estimated, which represents about 5.2% of the global and nearly 10% of the national population of this species. Cassin?s Auklets are also present in globally significant numbers with about 25,800 pairs being estimated on the Rankine Islands (about 1.4% of the world?s population). Nationally significant populations of Fork-tailed Storm-Petrels (at least 1%) and Leach?s Storm-Petrel (greater than 2% of the eastern Pacific population) are also present among the islands.

Other seabirds nesting on the islands include Pigeon Guillemots and Glaucous-winged Gulls. Black Oystercatchers are also present with as many as 8 pairs being estimated in the mid-1980s. The marine waters surrounding the island colonies provide important feeding habitat for marine birds. Bald Eagles nest on each of the islands and Peregrine Falcons (ssp. pealei) are recorded in the area.

Summary of bird records available for Rankine and Langtry Islands
Click here to view all records
Species Season Number Unit Date
Ancient Murrelet BR 26,200 G P 1985
Bald Eagle BR
Black Oystercatcher BR
Cassin’s Auklet BR 25,800 G P 1985
Colonial Waterbirds/Seabirds BR 66,300 G P 1985
Fork-tailed Storm-Petrel BR 2,000 N P 1985
Leach’s Storm-Petrel (E. Pacific) BR 12,300 G P 1985
Peregrine Falcon (pealei) BR
Pigeon Guillemot BR
Note: species shown in bold indicate that their population level (as estimated by the maximum number) exceeds at least one of the IBA thresholds (national, continental or global). The site may still not qualify for that level of IBA if the maximum number reflects an exceptional or historical occurence.
Conservation Issues

Rankine and Langtry Islands are located within the Gwaii Haanas National Park Reserve. Prior to the formation of this reserve, Rankine Islands were designated as a British Columbia Provincial Ecological Reserve (since 1973). The primary threats to the area are from potential oil spills, and possible disturbance from boaters and other visitors. The seabird colonies are fragile, particularly the storm-petrel colonies on Langtry and east Rankine Island. The spread of introduced predators (mainly raccoons, which are found on nearby Moresby Island, is also a potential threat.