Parks Canada aims to make seabird island IBAs rat-free
By nick.langley, Fri, 20/09/2013 - 13:20
Following a pilot eradication on two smaller islets, Parks Canada staff are clearing invasive rats from two important seabird breeding islands in the north of the Gwaii Haanas National Park Reserve and Haida Heritage Site on the archipelago of Haida Gwaii, a dense chain of islands in the Pacific off the coast of British Columbia.
Rat bait containing a rodenticide is being dropped on the islands by helicopter, a technique first developed in New Zealand, and also used by BirdLife to restore seabird breeding islands in the South Pacific.
The Haida Gwaii archipelago includes many Important Bird and Biodiversity Areas (IBAs) recognised for their populations of breeding seabirds. Parts or all of nine IBAs are protected by the Gwaii Haanas National Park Reserve, National Marine Conservation Area Reserve and Haida Heritage Site.
“Half the world population of Ancient Murrelet Synthliboramphus antiquus breed on Haida Gwaii, and approximately half of these breed within the Gwaii Haanas National Park Reserve”, said Laurie Wein, the project’s manager at Parks Canada.
One of the two target islands, Murchison, lies within the Ramsay and Northern Juan Perez Sound Islands IBA, which also meets IBA criteria for its population of Cassin’s Auklet Ptychoramphus aleuticus.
The Ancient Murrelet population is decreasing in North America. The global population is also suspected to be in decline owing to predation by invasive species, especially rats. Parks Canada is carrying out the eradication work in conjunction with the Haida Nation.
“The introduction of rats to many of the forested islands of Haida Gwaii has meant the demise of several historic seabird nesting colonies,” said Haida Nation president Peter Lantin. “Of particular interest is the Ancient Murrelet, a species at risk.
Also known as SGin Xaana or Night Bird, this was once an important food source for our people.” Parks Canada representatives attended the 2013 BirdLife World Congress in Ottawa, Canada, to speak about their work in the islands.
"Nature Canada applauds the leadership of Parks Canada in the restoration of these globally important bird areas,“ said Stephen Hazell, Senior Conservationist at BirdLife co-Partner Nature Canada. "The coastal areas around Haida Gwaii are a global hotspot for marine breeding birds, and efforts to rid the islands of rats are a first step towards restoring the ecological integrity of these islands.”
The rats, which were brought by ships in the 18th and 19th centuries, eat eggs and chicks, and attack adult murrelets and other ground- and hole-nesting species. Ramsay Island, the largest and most important seabird breeding island in the Ramsay and Northern Juan Perez Sound Islands IBA, is currently rat-free.
But as long as rats remain within the group, there is the ever-present danger that they could be accidentally introduced from nearby islands.
“Introduced predators are a major threat to colonial ground-nesting seabird species, including murrelets and storm petrels,” said Jon McCracken, Director of National Programs for Bird Studies Canada (BirdLife co-partner) and co-chair of the birds subcommittee for COSEWIC, the Committee on the Status of Endangered Wildlife in Canada. “Bird Studies Canada is strongly supportive of efforts by Parks Canada and the Haida Nation to protect seabirds by eliminating rats from islands in the Haida Gwaii.”
Populations of Endangered Marbled Murrelet Brachyramphus marmoratus, Leach’s Oceanodroma leucorhoa and Fork-tailed Storm-Petrel O. furcata, and Black Oystercatcher Haematopus bachmani are also expected to recover once the rats are gone.