Night Birds Returning, Haida Gwaii, British Columbia, Canada
Night Birds returning to Gwaii Haanas National Park Reserve, National Marine Conservation Area Reserve, and Haida Heritage Site, Haida Gwaii, British Columbia
The islands within Gwaii Haanas National Park Reserve, National Marine Conservation Area Reserve, and Haida Heritage Site (“Gwaii Haanas”) represent extremely important habitat for a variety of marine birds during the breeding and non-breeding seasons. In 2008, an 18,000 ha region in Juan Perez Sound that includes Ramsay, Murchison, House, and Hotspring islands was designated as a North America Important Bird Area (IBA) by BirdLife International, primarily to conserve seabird nesting sites. Arichika and the Bischof islands also lie within Juan Perez Sound and near the Ramsay and Northern Juan Perez Sound Islands IBA, where invasive rats are known to have caused serious impact to at least eight seabird colonies.
In 2009, Parks Canada Agency and the Haida Nation, who cooperatively manage Gwaii Haanas, launched SGin Xaana Sdiihltl’lxa, which means “Night Birds Returning” in the Haida language and refers to the habit of Ancient Murrelets (Synthliboramphus antiquus) to arrive and depart from their underground nests only at night. The project aims to restore nesting seabird populations and improve the ecological integrity of island ecosystems in Gwaii Haanas, while building awareness and understanding among Canadians about the impacts of introduced species on Gwaii Haanas’ natural and cultural heritage.
The eradication of invasive rats is necessary to reduce predation pressure on seabirds and improve important breeding habitat. This project will also restore breeding habitat for marine birds by establishing a rat-free zone of 12 islands within Juan Perez Sound. It is anticipated that the 1–2 million breeding pairs of marine birds, including seabirds, shorebirds, and sea ducks, nesting on adjacent islands will provide seed populations for recolonization of the project islands (Arichika, the Bischofs, Murchison, and Faraday). Eradicating invasive rats from these islands will likely also benefit intertidal flora and fauna and native rodent populations, including that of the dusky shrew (Sorex monticolus), due to reduced food competition and predation.
Phase 1: 2011 – Arichika and the Bischof Islands
The first phase of the Night Birds Returning project involved the eradication of Norway rats (Rattus norvegicus) from Arichika and the Bischof islands, which were home to large colonies of Ancient Murrelets (Synthliboramphus antiquus), Fork-tailed Storm Petrels (Oceanodroma furcata), Leach’s Storm Petrels (Oceanodroma leucorhoa), Rhinocerous Auklets (Cerorhinca monocerata), and other ground nesting seabirds prior to rat invasion.
The eradication operation on Arichika and the Bischof islands was completed in the fall of 2011. Since then, evidence of breeding Ancient Murrelets on Arichika Island has been reported. Increased abundance of breeding Fork-tailed Storm Petrels, Leach’s Storm Petrels, and Pigeon Guillemots (Cepphus columba) has also been observed on the Bischof islands, along with positive changes to the native vegetation. The road to full ecosystem recovery is long but these results suggest that the process is already underway.
Phase 2: 2013 – Murchison and Faraday Islands
In September 2013, Coastal Conservation and Parks Canada Agency implemented Phase 2 of the Night Birds Returning project: the eradication of black rats from Murchison and Faraday islands, to the north of Ramsay Island and within Juan Perez Sound. This was Canada’s first eradication of black rats using an aerially broadcasted rodenticide.
An aerial broadcast operation using pelleted rodenticide bait was the method of choice due to the size of the islands and the presence of challenging topography. This technique has become the most common method of rodenticide delivery on large islands internationally and has been used in the majority of successful eradications worldwide.
International eradication experts from New Zealand, Mexico, and the United States were involved in the planning and implementation of Phase 2 to maximize the probability of eradication success while minimizing impacts to native species during the eradication operation. Two years of detailed planning and preparations were undertaken prior to implementation.
The Night Birds Returning project islands were declared rat-free in 2016, following monitoring during a two-year post-eradication waiting period designed to provide sufficient time for any residual rat populations to increase to detectable levels. Since the completion of rat eradication work in 2013, signs of ecological recovery have become evident on many of Gwaii Haanas’ rat-free islands. One example is the increased number of nests and successful chick-rearing by Black Oystercatchers, a species that acts as a sentinel for changes in coastal ecosystem health. Another native species, the Dusky shrew, is also making a comeback since the rats were removed. Parks Canada Agency has implemented an on-going monitoring program to measure rat presence/absence on these islands over the coming years.
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