The St Helena plover or Wirebird (Charadrius sanctaehelenae) is the only remaining endemic bird species on St Helena. The Wirebird is one of only four Critically Endangered bird species in the UK and its Overseas Territories and is therefore a priority target for conservation action. The Wirebird was recently classified as Critically Endangered when it suffered a catastrophic decline (40% in 5 years) to only 200 individuals. Recent censuses indicate that the population has stabilised to approximately 350 individuals, due in large part to an extensive programme of habitat improvement which is due to finish in 2011.
The impact of invasive predators on Wirebird numbers is known to be a significant obstacle to sustainable species recovery. Predation accounts for over 90% of failed Wirebird nests. A recent project by the RSPB and the University of Bath demonstrated using cameras that cats (both domestic and feral) are the most damaging predator (65% of all recorded nest predations). The research demonstrated a direct correlation between Wirebird nest survival and density of cats: Wirebird nest survival was shown to be up to 50% lower at sites with a higher density of cats. The study also found that rats were responsible for 15% of nest predations. In the most severely impacted areas nests have less than a one in five chance of survival. Cat predation has been implicated in limiting chick survival to fledgling, which has been estimated to be only one in three (36%). This means that in some cases for every fifteen Wirebird nests only one nest successfully produces fledglings. A reduction in current predation rates would therefore significantly improve the fragile conservation status of the Wirebird, and has been highlighted in a recent report as one of the top priorities for the UK Overseas Territories (1).
The project will undertake intensive predator control at the three main Wirebird sites on the island (a fourth site will be used as a control). Cats will be caught and removed using cage traps with the involvement of the ANRD vet and SPCA. Feral cats will be disposed of humanely under the supervision of the ANRD, as part of a feral cat control programme developed following a recommendation made by the Government vet (2). Pet cats will be recorded on a new pet database; their owners will be traced, the cats microchipped and neutering, if needed, will be encouraged. Their movements will then be monitored to assess their likely impact on Wirebirds. Rodent control will be undertaken according to the methodology developed by the recent South Atlantic Invasive Species project, which included a fully developed rat baiting programme for one of the proposed control sites at Deadwood Plain (3).
The intensity of predator control required will be adjusted from the population model developed at University of Bath. The number of predators at each site will be regularly monitored (using index trapping, tracking tunnel and Waxtag survey methods) to assess how successful the control programme has been in reducing predator densities. At the same time Wirebird nest and brood survival rates will be closely monitored. From this it will be possible to assess the impact of predator control on Wirebird population levels. This information will be used to inform Wirebird conservation initiatives delivered on St Helena, including the development and implementation of Wirebird predator control plans for the three main sites. Responsibility for implementing these plans will then fall under rodent control programmes carried out by ANRD, Environmental Health and the National Trust.
(1)The catastrophic impact of invasive mammalian predators on birds of the UK Overseas Territories: a review and synthesis, Geoff M. Hilton & Richard J. Cuthbert (2010) (2) Veterinary Support Officer Final Report, Jonathan D. Hollins (2009) (3) Rats on St Helena: Improving Rodent Control on St Helena, Elizabeth Bell and Kevin Floyd (2009)
- Wirebird productivity increased;
- Predator density at control sites reduced;
Wirebird site predator control plans produced;
- Staff trained in Wirebird predator control;
- Long-term Wirebird predator control programme underway;
- Responsible pet ownership programme underway
Under Output 1:
Under Output 2
- Monitor Wirebird productivity and survival. The Wirebird Monitoring Officer (WMO) will monitor and record the productivity and survival of colour ringed Wirebirds throughout the project at the four study sites. Nests and broods will be visited each week to assess survival to hatching and to fledging. All known Wirebird sites on the island will be visited once a year and all colour-ringed birds recorded in order to estimate adult survival.
- Monitor and analyse trends in population numbers. Once a year a whole island census of Wirebirds will be organised by the WMO to assess the impact of predator control at a population level. The results of this data collection will be analysed by RSPB to determine the efficacy of predator control measures.
- Training in Wirebird monitoring. Project personnel and volunteers will be trained by the WMO to find and monitor Wirebird nests and broods. This will enable activity 2 to be successfully undertaken.
Under Output 3:
- Predator Control at Wirebird sites. Intensive control will be carried out at three sites throughout the duration of the project (a fourth will be a study control). Cats will be caught using cage traps to avoid unwanted mortality of domestic cats. Feral cats will be humanely destroyed under ANRD supervision. Pet cats will be neutered, microchipped and returned to their owners. Rodents will be controlled using bait, using the methodology developed by the recent South Atlantic Invasive Species project. The intensity of control required will be initially estimated from the population model developed at University of Bath, and from similar projects in the literature, and will be subject to ongoing adjustment in order to meet targets.
- Predator monitoring at all four study sites. Rodent densities will be monitored using tracking tunnels and cats will be monitored using trail cameras and scat deposition rates.
- Based on the outcomes of activities 2.1 and 2.2, a control plan will be produced for each site to guide predator control efforts. A general guidance document will be produced that will be applicable to new wirebird sites (e.g. sites developed or restored in association with the planned airport).
Under Output 4:
- On the job training for project staff. Project personnel will be trained in cat and rodent control and monitoring. This will serve to broaden the local skill base, to give the team a thorough understanding of each other's work, and to allow staff to help out in other activities as and when required.
- Training workshops for stakeholders. Workshops will be held to enable involvement of ANRD and EH pest control staff, land owners, neighbours, and other interested parties to learn about predator control for wirebirds, and to undertake such control if desired. This will further broaden the local skill base, which will be useful if control is extended to new sites in future.
Under Output 5:
- Meetings with ANRD and EH. Meetings with ANRD and EH decision-makers to ensure that predator control at Wirebird sites is built into departmental work programmes.
- Information dissemination to other UKOTs. Lessons learned from the predator control activities will be promoted to other UKOTs invasive predator problems in journal articles, on websites (eg National Trust site and South Atlantic Invasive Species discussion board) and through collaborative meetings.
Under Output 6:
- Construction of pet cat register. ANRD currently offer pet owners the chance to have their pet neutered and maintain a database of this information. This database will be extended to include information gathered during the project from the targeted visits to domestic properties and from an island wide call for information about pet ownership. It will be based on the Ascension Island Government cat owners' database.
- Encourage responsible pet ownership. Cat owners living adjacent to key Wirebird sites will be visited and will be encouraged to neuter their pet; to fit them with a PIT tag to allow unique identification and differentiation between domestic and feral cats; and to fit them with a quick release collar with a bell to reduce the cat's hunting efficiency. This activity will be undertaken by the project team in conjunction with the St Helena Society for the Prevention of Cruelty to Animals.
- Mapping of domestic cat home ranges. A sample of pet cats will be fitted with a GPS collar to monitor their movements. After two months these collars will be retrieved and home ranges mapped. The results will serve as an educational tool to show pet owners how far their cats are ranging and to encourage them to have their pets neutered. It will also be used as a tool in the classroom, allowing the students to understand more about biology and gain an introduction to GIS.
- Island wide education campaign. This campaign will seek to minimise domestic cats' impact on other wildlife by discouraging the release of cats or kittens into the wild, and encouraging pet owners to have their cats microchipped and fitted with a bell, and neutered where necessary. This activity will be led jointly by ANRD, St Helena National Trust and the St Helena Society for the Protection of Animals and will involve public talks, school talks and items on local radio and in local newspapers.
Risk 1: Predator control ineffectual. Fail to catch animals or rapid re-colonisation
Management: Control measures have already been used successfully elsewhere
Responsive management: increase intensity of predator control or modify techniques if current ones are proving ineffectual
Education campaign seeks to reduce number of animals released and therefore reduce the re-colonisation rate.
Risk 2: Lack of public support for cat control
Management: Public awareness programme involving ANRD/the Government vet, SPCA and the National Trust. This will emphasise how control can be minimised through responsible pet ownership and the animal welfare benefits of feral cat control (feral cats currently suffering from multiple diseases including cat FIDS which can be spread to pet cats).
Promote economic importance of Wirebird to increased eco-tourism
Risk 3: Unexpected trophic responses to reduction in predator densities
Management: Control measures have already been used successfully elsewhere.
By targeting both cats and rodents at the same time the potential for trophic responses is greatly reduced.
Organisations or stakeholder groups directly benefiting from the project:
The St Helena community will benefit from the improved conservation of its national bird. Tourism providers will benefit from the eco-tourism opportunities this supports.
The St Helena National Trust and the Agriculture and Natural Resources Department (ANRD) will benefit from increasing their capacity for invasive predator control and Wirebird conservation.
The agricultural sector will benefit from a reduction in invasive pest species in areas of production.
The Society for the Prevention of Cruelty to Animals (SPCA) will benefit from improved animal welfare standards.
Eco-tourism is a small but growing sector on St Helena supporting a handful of tour companies. Increased Wirebird numbers will support a greater number of birdwatching tours. The control of rats in productive agricultural areas will have a positive impact on farmers and growers.
Multilateral Environmental Agreements
The project will make a strong contribution to the implementation of St Helena's Environment Charter and its Strategy for Action, specifically the following:
2. Ensure the protection and restoration of key habitats, species and landscape features through legislation and appropriate management structures and mechanisms, including a protected areas policy, and attempt the control and eradication of invasive species.
2.c.6 Wirebird Working Group to identify opportunities to improve conservation of this species.
2.e. Eradicate problem invasive species.
7. Review the range, quality and availability of baseline data for natural resources and biodiversity
7.a.15. Strengthen biannual monitoring of Wirebird.
7.a.25. Monitor invasive species and their impacts, as well as endemics.
The project will carry out key activities under the St Helena Wirebird Species Action Plan, especially under Objective 5: Improve understanding of and reduce the impact of predators on survival and productivity of the Wirebird.
The project will contribute to the effective implementation of the Convention on Biological Diversity, which has been extended to St Helena. In particular, the project will contribute to implementation of the following CBD Articles:
7. Identification and Monitoring (all)
8. In-situ Conservation (d, f, h, k)
13. Public Education and Awareness (all)
This Project will also contribute to the following from the St Helena Government's Policy and Planning priorities:
Strategic Objective 1.2.2 Ensure protection and conservation of St Helena's terrestrial marine and built environment. Priority - Develop, fund and implement a medium to long term coherent and appropriate environmental conservation policy that promotes the establishment of self-sustaining habitats, improves the status of our endemic species and results in an informed and responsive society.
Funded by FCO/DFID Overseas Territories Environment Programme, 2011, project no STH 805