Tony Martin (Centre for Remote Environments, University of Dundee, UK) and Mike Richardson have published open access in the conservation journal Oryx on the eradication attempt made to remove introduced rodents on the island of South Georgia/Islas Georgias del Sur*.

The paper’s abstract follows:

“The Subantarctic island of South Georgia lost most of its birds to predation by rodents introduced by people over 2 centuries. In 2011 a UK charity began to clear brown rats Rattus norvegicus and house mice Mus musculus from the 170 km long, 3,500 km island using helicopters to spread bait containing Brodifacoum as the active ingredient. South Georgia’s larger glaciers were barriers to rodent movement, resulting in numerous independent sub-island populations. The eradication could therefore be spread over multiple seasons, giving time to evaluate results before recommencing, and also reducing the impact of non-target mortality across the island as a whole. Eradication success was achieved in the 170 km Phase 1 trial operation. Work in 2013 (Phase 2) and early 2015 (Phase 3) covered the remaining 128 km occupied by rodents. By July 2017, 28 months after baiting was concluded, there was no sign of surviving rodents, other than one apparently newly introduced by ship in October 2014. A survey using detection dogs and passive devices will search the Phase 2 and Phase 3 land for rodents in early 2018. Seven (of 30) species of breeding birds suffered losses from poisoning, but all populations appear to have recovered within 5 years. The endemic South Georgia pipit Anthus antarcticus was the first bird to breed in newly rat-free areas, but there were also signs that cavity-nesting seabirds were exploring scree habitat denied them for generations. Enhanced biosecurity measures on South Georgia are needed urgently to prevent rodents being reintroduced.

A helicopter flies over the island of South Georgia/Islas Georgias del Sur* spreading poison bait

Reference:

Martin, A.R. & Richardson, M.G. 2017. Rodent eradication scaled up: clearing rats and mice from South Georgia. Oryx doi.org/10.1017/S003060531700028.

John Cooper, ACAP Information Officer, 25 September 2017

*A dispute exists between the Governments of Argentina and the United Kingdom of Great Britain and Northern Ireland concerning sovereignty over the Falkland Islands (Islas Malvinas), South Georgia and the South Sandwich Islands (Islas Georgias del Sur y Islas Sandwich del Sur) and the surrounding maritime areas.

Rémi Fay (Centre d'Etudes Biologiques de Chizé, Villiers-en-Bois, France) and colleagues have published in the journal Ecological Monographs on differences in the quality of life-history traits in the Wandering Albatross Diomedea exulans.

The paper’s abstract follows:

“Although population studies have long assumed that all individuals of a given sex and age are identical, ignoring among-individual differences may strongly bias our perception of eco-evolutionary processes. Individual heterogeneity, often referred to as individual quality, has received increasing research attention in the last decades. However, there are still substantial gaps in our current knowledge. For example, there is little information on how individual heterogeneity influences various life-history traits simultaneously, and studies describing individual heterogeneity in wild populations are generally not able to jointly identify possible sources of this variation. Here, based on a mark-recapture data set of 9,685 known-aged wandering albatrosses (Diomedea exulans), we investigated the existence of individual quality over the whole life cycle of this species, from early-life to senescence. Using finite mixture models, we investigated the expression of individual heterogeneity in various demographic traits, and examined the origin of these among-individual differences by considering the natal environmental conditions. We found that some individuals consistently outperformed others during most of their life. At old age, however, senescence rate was stronger in males that showed high demographic performance at younger ages. Variation in individual quality seemed strongly affected by extrinsic factors experienced during the ontogenetic period. We found that individuals born in years with high population density tended to have lower performances during their lifespan, suggesting delayed density dependence effects through individual quality. Our study showed that among-individual differences could be important in structuring individual life history trajectories, with substantial consequences at higher ecological levels such as population dynamics.”

A Wandering Albatross at its nest, photograph by Kate Lawrence

Reference:

Fay, R., Barbraud, C., Delord, K. & Weimerskirch, H. 2017. From early-life to senescence: individual heterogeneity in a long-lived seabird. Ecological Monographs. doi:10.1002/ecm.1275F.

John Cooper, ACAP Information Officer, 22 September 2017

A three-year project to create a new colony of Laysan Albatrosses Phoebastria immutabilis in the James Campbell National Wildlife Refuge on the Hawaiian island of Oahu has been completed with a 92% fledging rate. The hand-reared chicks have come from eggs removed from the Pacific Missile Range Facility Barking Sands on the nearby island of Kauai.

Hand-reared Laysan Albatross chicks waiting for a feed

“17 Laysan Albatross fledged from James Campbell NWR this summer. The project’s goal is to match the fledging success of wild birds, which ranges from 60 to 80 percent. The first two years saw 29 chicks fledge with relatively few issues apart from the ever-present stench of fish slurry and the nights of worry that go with raising seabird chicks from hatching to fledging. ... After three years, 46 chicks had fledged out of 50 relocations, putting the fledging rate at 92 percent - far above the fledging success of wild birds. After spending three to five years at sea, these chicks will hopefully return to the place they were raised - James Campbell NWR … and start the process of selecting a mate for breeding. If they do, the project will be deemed a success …”.

Hand-reared Laysan Albatross chicks keep to the shade in the James Campbell National Wildlife Refuge

Read previous ALN postings on translocated albatrosses at the James Campbell NWR.

Read more here on year three of the project:

John Cooper, ACAP information Officer, 21 September 2017

Julie McInnes (Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia) and colleagues have an accepted paper awaiting on-line publication in the journal Frontiers in Marine Science that uses use DNA metabarcoding of Black-browed Albatross Thalassarche melanophris faeces to identify fish prey, including bycatch species.

The paper’s abstract follows:

“Almost all of the world’s fisheries overlap spatially and temporally with foraging seabirds, with impacts that range from food supplementation (through scavenging behind vessels), to resource competition and incidental mortality. The nature and extent of interactions between seabirds and fisheries vary, as does the level and efficacy of management and mitigation. Seabird dietary studies provide information on prey diversity and often identify species that are also caught in fisheries, providing evidence of linkages which can be used to improve ecosystem based management of fisheries. However, species identification of fish can be difficult with conventional dietary techniques. The black-browed albatross (Thalassarche melanophris) has a circumpolar distribution and has suffered major population declines due primarily to incidental mortality in fisheries. We use DNA metabarcoding of black-browed albatross scats to investigate their fish prey during the breeding season at six sites across their range, over two seasons. We identify the spatial and temporal diversity of fish in their diets and overlaps with fisheries operating in adjacent waters. Across all sites, 51 fish species from 33 families were identified, with 23 species contributing >10% of the proportion of samples or sequences at any site. There was extensive geographic variation but little inter-annual variability in fish species consumed. Several fish species that are not easily accessible to albatross, but are commercially harvested or by-caught, were detected in the albatross diet during the breeding season. This was particularly evident at the Falkland Islands and Iles Kerguelen where higher fishery catch amounts (or discard amounts where known) corresponded to higher occurrence of these species in diet samples. This study indicates ongoing interactions with fisheries through consumption of fishery discards, increasing the risk of seabird mortality. Breeding success was higher at sites where fisheries discards were detected in the diet, highlighting the need to minimise discarding to reduce impacts on the ecosystem. DNA metabarcoding provides a valuable non-invasive tool for assessing the fish prey of seabirds across broad geographic ranges. This provides an avenue for fishery resource managers to assess compliance of fisheries with discard policies and the level of interaction with scavenging seabirds.”

Black-browed Albatross, photograph by Aleks Terauds
 

Reference:

McInnes, J.C., Jarman, S.N., Lea, M.-A., Raymond, B., Deagle, B.E., Phillips, R.A., Catry, P., Stanworth, A., Weimerskirch, H., Kusch, A., Gras, M., Cherel, Y., Maschette, D & Alderman, R. 2017. DNA metabarcoding as a marine conservation and management tool: a circumpolar examination of fishery discards in the diet of threatened albatross. Frontiers in Marine Science doi: 10.3389/fmars.2017.00277.

John Cooper, ACAP Information Officer, 20 September 2017