SG̲in X̲aana Sdiihltl’lx̲a: Night Birds Returning
Gwaii Haanas National Park Reserve, National Marine Conservation Area Reserve, and Haida Heritage Site
SG̲in X̲aana Sdiihltl’lx̲a: Night Birds Returning
How to Pronounce SGin Xaana Sdiihltl’lxa in Xaayda Kil
Seabirds at risk
Ancient Murrelets (or "night birds" as translated from the Haida language) are a species at risk in Canada. Their population in Gwaii Haanas has been devastated by invasive rats.
Between 2011 and 2013 a major ecosystem restoration project called SG̲in X̲aana Sdiihltl’lx̲a: Night Birds Returning took place in Juan Perez Sound to remove rats from select islands.
SG̲in X̲aana Sdiihltl’lx̲a: Night Birds Returning has resulted in successful habitat restoration following the project. However, rats have been detected migrating across islands in recent years. The Haida Nation, Parks Canada and Fisheries and Oceans Canada are working together to continue protecting Ancient Murrelet habitat.
An irreplaceable habitat
A significant number of the world population of Ancient Murrelets breed on remote islands in Gwaii Haanas. These seabirds spend most of their lives on the water. They only come and go from small islands during breeding season.
Ancient Murrelets breed by night laying two eggs in a burrow. Hidden under the forest floor, the tiny chicks hatch. Within days, the chicks scuttle through the night-shaded undergrowth. They follow the sound of their parents as they are called to the sea.
These seabirds also once played an important role in the diet of the Haida. The colonies were once prime food gathering places.
Devastated by rats
Rats were first introduced to Haida Gwaii with the advent of maritime shipping in the late 1700s. Two types of invasive rats are currently found in Gwaii Haanas: black rats and Norway (brown) rats. They are known to occur on at least 18 islands throughout the archipelago. Their presence has had a devastating effect on the seabirds of Gwaii Haanas, eating eggs, young and even nesting adult seabirds. This has caused the birds to abandon many rat-infested islands.
The projects: Restoring habitat by removing rats
Parks Canada, the Haida Nation and several international partners are committed to restoring seabird habitat on several remote islands in Gwaii Haanas.
SG̲in X̲aana Sdiihltl’lx̲a: Night Birds Returning aimed to restore habitat and improve ecological integrity. This project launched in 2009 with phase one occurring in 2011, and phase two in 2013. Both phases focused on the eradication of invasive rat species on specific islands. This includes Arichika, the Bischofs, G̲aysiigas Gwaay (Murchison), and Daa.a Gwaay (Faraday). The eradication of rats is necessary to improve habitat for Ancient Murrelets and other seabirds in Gwaii Haanas.
The protection of species at risk is a high priority for Parks Canada. Through initiatives like this, Parks Canada is achieving conservation results.
Phase one: 2011
In 2011, Parks Canada, the Haida Nation, Island Conservation and Coastal Conservation implemented the eradication of invasive Norway rats from Arichika and Bischof islands. Arichika and Bischof islands were once home to significant Ancient Murrelet colonies. This work was supported by Parks Canada’s Action-on-the-Ground program. This program funded ecological restoration across Canada’s national parks. It was also funded by the US Coast Guard’s Oil Spill Liability Trust Fund. This fund was set up to offset the damage done to seabirds by a sunken oil tanker, the S.S. Jacob Lukenbach. It went down in 1953 off the coast of California.
A three-month ground-based eradication effort was carried out by field crews. This operation involved using a rodenticide in the specialized stations. Daily monitoring and removing rat carcasses by hand also took place.
Results on Arichika and Bischof islands
- Scientists successfully managed for the possibility that other species could have been affected by the eradication. This resulted in very few impacts on other species and no population-level impacts.
- Within years, populations of native shrews on Arichika and Bischof islands returned to levels comparable to islands without rats.
- Immediately after the removal of rats, Black oystercatcher numbers started increasing and fledging more chicks. Black oystercatchers are a shorebird. They are considered by scientists to be a sentinel species. This means that they respond quickly to changes in ecosystem health.
- As of 2019 Arichika Island remains rat-free. Seabird calls captured on acoustic recording units continue to increase.
- Eradication on the Bischof Islands was also successful. However, several rats have been detected recently. It is believed these rats have re-invaded from the neighbouring Lyell island, or from elsewhere.
Phase two: 2013
In September 2013, the eradication of black rats took place on Murchison and Faraday islands. Collaboration took place between Parks Canada and the Haida Nation, and its partners Coastal Conservation and Island Conservation. Parks Canada also drew on technical expertise from international experts in New Zealand and Mexico. Financial contribution came 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. This area includes islands 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 at the time was rat-free. The removal of rats on these two islands aimed to reduce the risk of a rat invasion to nearby intact seabird colonies.
The eradication of black rats from Murchison and Faraday islands was completed by helicopter. Bait containing a rodenticide was dispensed from the air using a device made for the project. The device allowed bait to be dropped in precise locations. The rodenticide was also tailor-made for the project to be as unattractive as possible to non-target species.
This aerial technique is similar to aerial seeding applications used in forest or agricultural management. It is also a proven conservation management technique for removing rats from islands and restoring native species. It has been used extensively in New Zealand, Mexico, the United States and the Galapagos.
Results on Murchison and Faraday islands
- Following the eradication, native species started responding to the absence of rats. In 2016, a six per cent increase in the calls of Ancient Murrelets on both islands was observed. Detection was through the use and analysis of automated acoustic listening devices.
- Gwaii Haanas field staff observed more shore crabs in the intertidal zone on both islands. More crabs indicate less rats living on those islands.
- Black oystercatcher numbers started increasing on Murchison and Faraday islands following the removal of rats from the islands.
- In 2016, after continued monitoring Murchison and Faraday Islands were declared rat free.
- In September 2017, wildlife cameras set to detect small mammals showed evidence of Norway rats on Murchison and Faraday islands. This species is new to these islands. Their population is considered low at this time.
- There continues to be no evidence of black rats on Murchison and Faraday islands.
Continued monitoring and research
Monitoring and research has continued since Norway rats were detected on Murchison and Faraday islands in 2017.
In order to determine where the Norway rats on Murchison and Faraday came from, DNA samples were sent to University of British Columbia Okanagan. Results found that these rats are related to rats on Tllga Kun Gwaay (Lyell Island). Lyell Island is one of the larger landforms in Gwaii Haanas. It is located to the north, less than 1 kilometre away. It is still unknown how the rats got across to Murchison and Faraday islands. It could have been by swimming, drifting on a log or via a vessel.
In September 2018, wildlife cameras picked up evidence that Norway rats had migrated to G̲andll K’in Gwaay.yaay (Hotspring Island) and Aataana Gwaay.yaay (House Island). Rodenticide was distributed on Hotspring and House islands and islets in November to eradicate an estimated 6-12 rats.
In July 2019, Norway rats were discovered on Taw HlG̲aahl Gwaayts’ads (Tar Island), and K’aadxwa Xyangs Gwaayts’ads (Agglomerate Island), followed by Xiina Gwaay.yaay (Ramsay Island) and again on Hotspring Island in August 2019. This is the first time rats have been detected on Tar, Agglomerate and Ramsay islands.
Ongoing Monitoring and Next steps
To find out more about rat population dynamics, data continues to be collected and analyzed. Time is also being spent carefully analyzing past restoration and biosecurity efforts to plan a future response. Before any further conservation work on invasive species occurs, local and international partners are assisting the Gwaii Haanas team to determine next steps and biosecurity measures. An Invasive Species management plan is being developed to better understand invasive species and the direction that should be taken.
Help prevent the spread of rats
Travelling to Gwaii Haanas? Rats are great stowaways. Help prevent rats from being introduced to more islands. This can be done by maintaining a rat-free vessel.
- Keep food, waste and gear in rat-proof, sealed storage areas.
- Inspect your boat regularly for signs of rats. This includes droppings, nests and chewed food, wood or wires.
- Know which anchorages have rats nearby.
- Clean up any debris that could shelter rats.
- Use rat guards on ship-to-shore lines to prevent rats boarding at ports.
- Install traps on your boat.
- Seal all entry points on your boat. Rats can crawl through holes as small as 1 cm.
- Never throw a rat overboard, they are good swimmers and may reach land.
Gwaii Haanas provides all boaters travelling to the area free Rat Aware Kits.
Happy rat-free sailing!
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