Conserving islands and their birds
Oceanic islands hold a disproportionately large amount of terrestrial biodiversity, yet are extremely vulnerable to introduced species: more than 90% of recent bird extinctions have been of island birds. Fortunately, eradicating invasive species can restore island ecosystems, provided there are strict controls on the import of people and materials. Birds are flagships for the conservation-management and restoration of island ecosystems.
Our work focuses on South Africa’s Prince Edward Islands and the UK Overseas Territory of Tristan da Cunha and Gough Island. We are mainly concerned with the impacts of introduced predators, specifically House Mice Mus musculus, but also are involved in the eradication or control of introduced plants at Gough Island and the uninhabited islands in the Tristan archipelago. The impacts of House Mice on seabirds were only discovered in the early 2000s, following research by Fitz students in collaboration with the Royal Society of the Protection of Birds at Gough Island. Since then, they have been found to attack seabird chicks on Marion Island, and recently have even been found to attack adult albatrosses at colonies in the North Pacific Ocean.
Activities in 2016
- Regular surveys were conducted from March to May 2016 to monitor the spread of mouse attacks on large chicks of Grey-headed Albatrosses Thalassarche chrysostoma and sooty albatrosses Phoebetria spp. at Marion Island. Attacks were just as extensive and widespread as in 2015, and the occurrence of attacks at widely spaced locations all around the coast of Marion Island indicate that the behaviour is evolving independently at multiple sites. However, there are some consistent hot-spots, which might reflect cultural transmission among mice at specific locations.
- Ben Dilley and Delia Davies completed their contract with the Tristan government to help train Tristan Conservation Department staff. They were then appointed to an EU-BEST project awarded to Tristan Conservation to collect basic biology information on Wilkins’ Bunting Nesospiza wilkinsi. They spent the summer of 2016/17 on Nightingale Island, ringing large numbers of individuals to obtain robust survival estimates, and found 49 nests, allowing the first estimate of breeding success of this Endangered species.
- Sagina procumbens control/eradication operations continued on Gough Island throughout 2016. The new regime spraying with a combination of pre-emergent and standard herbicides appears to be making a difference, with decreasing numbers of seedlings detected in successive summers.
- Two papers were published on the impacts of introduced mice on birds at Marion Island in 2016; one reported massive increases in attacks on albatross chicks at Marion Island (Dilley et al. Antarctic. Sci.) and one showed how Brown Skua Stercorarius antarcticus diets haven’t changed since the eradication of cats on Marion, suggesting that the recovery of burrowing petrel populations is being hampered by mice (Cerfonteyn and Ryan Antarctic. Sci.). A further paper showing limited recovery of petrel populations is still in press (Dilley et al. Antarctic. Sci.). Data from this study was contributed to a meta-analysis on recovery of seabird populations following restoration programmes (Brooke et al. in press, Anim. Conserv.).
- Peter Ryan is one of many co-authors on a paper reviewing the impact of light pollution on seabirds (Rodriguez et al. in press Conserv. Biol.).
- A paper summarising the biology of Gough Island mice was finally published (Cuthbert et al. 2016, J. Mammal.).
- A paper on the clinical pathology of the Gough Bunting Rowettia goughensis was accepted for publication (Dagleish et al. 2017, J. Comp. Pathol.). This study, and a similar one on Gough Moorhens Gallinula comeri, forms part of the preparation for taking insurance populations of buntings and moorhens into captivity during the mouse eradication attempt on Gough Island planned for the winter of 2019.
- Frederik Paulsen, sponsor of the Antarctic Circumnavigation Expedition, was so horrified by the antics of the mice on Marion that he donated the three helicopters used to eradicate rats and mice from South Georgia to the South African Department of Environmental Affairs (DEA) on condition that they are made available for mouse eradication attempts on Gough and Marion Islands. He also donated $100,000 to DEA on production of a plan to eradicate mice from Marion Island. This has stimulated DEA to announce plans for an eradication attempt on Marion in 2020, if the Gough eradication goes ahead in 2019.
Agreement on the Conservation of Albatrosses and Petrels; BirdLife International; DST-NRF CoE grant; EU-BEST; Royal Society for the Protection of Birds; South African National Antarctic Programme; UK Overseas Territories Environment Programme..
Prof. Peter Ryan (FIAO, UCT)
Dr Alex Bond (RSPB)
Dr Richard Cuthbert (RSPB)
Trevor Glass (Tristan Conservation Department)
Dr Ross Wanless (FIAO, UCT and BLSA)
Students: Ben Dilley (PhD)
Research assistants: Jan Bradley, Derren Fox, Chris Taylor (Gough 2015/16), Emma Witcutt, David Kinchin-Smith and Phil Lambdon (Gough 2016/17) and Delia Davies.