SGin Xaana Sdiihltl’lxa: Night Birds Returning
SGin Xaana Sdiihltl’lxa: Night Birds Returning
Seabirds at risk
Ancient Murrelets (or "night bird" as translated from the Haida language), a species at risk in Canada, are being devastated by invasive rats.
A significant proportion of the world population of these seabirds breed on remote islands in Gwaii Haanas National Park Reserve, National Marine Conservation Area Reserve, and Haida Heritage Site.
Parks Canada, the Haida Nation and several international partners are committed to restoring seabird habitat on several remote islands in Gwaii Haanas, by removing invasive rats.
The protection of species at risk is a high priority for Parks Canada. Through initiatives like this, Parks Canada is achieving conservation results in support of the National Conservation Plan.
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Ancient Murrelets come and go from small islands by night during breeding season and spend the rest of their time on the water.
Burrowed under the forest floor, the tiny chicks hatch and within days scuttle through the night-shaded undergrowth as their parents call to them from the sea.
These seabirds also once played an important role in the diet of the Haida people and the colonies were once prime food gathering places.
Devastated by rats
The birds have long since abandoned many rat-infested islands.
Rats, first introduced to Haida Gwaii with the advent of maritime shipping in the late 1700s, are known to occur on at least 18 islands throughout the archipelago and have had a devastating effect on several seabird colonies.
Phase one: 2011
In 2011, Parks Canada, the Haida Nation, Island Conservation and Coastal Conservation implemented a ground-based eradication of invasive Norway rats from Arichika and Bischof Islands, once home to significant ancient murrelet colonies. This work was supported by Parks Canada’s Action-on-the-Ground program which funds ecological restoration across Canada’s national parks and by the US Coast Guard’s Oil Spill Liability Trust Fund – a fund set up to offset the damage done to seabirds by a sunken oil tanker, the S.S. Jacob Lukenbach, which went down in 1953 off the coast of California.
- In 2011, field crews implemented a three month eradication effort. This operation involved using a rodenticide in the specialized stations, daily monitoring and the manual removal of rat carcasses on Bischof and Arichika Islands.
- The good news is that Arichika Island has been declared rat-free. While the eradication on the Bischof Islands was also successful, several rats have been detected recently. It is believe that these rats have re-invaded from a neighbouring island or from elsewhere.
- Scientists managed for the possibility that other species could have been affected by the eradication, and reported very few impacts on other species and no population-level impacts.
Phase two: 2013
In September 2013, an aerial eradication took place on Murchison and Faraday Islands (two larger islands within the park reserve). The work is a collaboration between Parks Canada and the Haida Nation, and its partners Coastal Conservation and Island Conservation. In addition, Parks Canada drew on technical expertise from international experts in New Zealand and Mexico and received financial contribution from the US National Fish and Wildlife Foundation – a non-governmental, charitable body established by the US Congress.
Murchison and Faraday Islands are located within the Juan Perez Sound, an area that includes islands which are recognized internationally for their globally outstanding seabird populations (Ancient Murrelets, Cassin’s auklets) and other seabird (Leach’s storm-petrels, Fork-tailed storm-petrels) and shorebird species.
Murchison and Faraday Islands are close to Ramsay Island, which is currently rat-free, and hence removal of rats here is necessary to reduce risk of rat invasion to these nearby intact seabird colonies.
The eradication of invasive rats from Murchison and Faraday Islands involves an aerial broadcast of bait containing a rodenticide dispensed by helicopter, very similar to aerial seeding applications used in forest management or agricultural applications. This is proven conservation management technique has been used extensively in New Zealand, Mexico, the United States and the Galapagos to remove rats from islands and restore native species.
Native species are already responding to the absence of rats. Populations of native shrews on Arichika and Bischofs islands are already at levels comparable to islands without rats.
Black oystercatchers, shorebirds which are considered by scientists to be sentinel species that respond quickly to changes in ecosystem health, are increasing in numbers and are fledging more chicks in the absence of rats. Automated acoustic listening devices have been deployed on these islands and on unaffected islands to measure seabird response to the eradication.
Scientists will study the frequency and distribution of the birds’ calls to gauge project success, as well as monitor a number of other ecosystem responses. In coming years, restoration techniques such as call play-backs may be employed to encourage the birds to re-colonize these islands.
In 2016, thanks to continued monitoring Murchison and Faraday Islands were declared rat free. Through the use and analysis of automated acoustic listening devices, a six per cent increase in the calls of Ancient Murrelets on both islands was observed.
Anecdotally, Gwaii Haanas field staff observed more shore crabs in the intertidal on both Murchison and Faraday, another indicator of less rats living on those islands.
Fall 2017 update
Active restoration of cultural and ecological integrity in Gwaii Haanas is a priority for the Archipelago Management Board: the Council of the Haida Nation and Government of Canada (Fisheries and Oceans Canada and Parks Canada). And through partnership and efforts by both Gwaii Haanas and many international organisations, we were able to rid Murchison, Faraday and Arichika of black rats.
In September 2017, biosecurity cameras set to detect small mammals on Murchison/Faraday Islands showed evidence of Norway rats on these islands. These rats are new to the islands. There continues to be no evidence of black rats. To figure out where these Norway rats have come from, we are analyzing the data we’ve captured through our monitoring program, including acoustic recording units, a summer of field observations remote camera monitoring.
In addition, since the incursion, Gwaii Haanas field team members have set up additional remote cameras on the Murchison and Faraday and are trapping rats using bait. Thanks to previous work with the UBC Okanagan (UBCO) genetics lab, we are running genetics analysis on rats from across the Haida Gwaii archipelago. Rats were trapped in the fall of 2017 and DNA samples to the UBCO lab to determine where the Norway rats on Murchison and Faraday are from.