The following shortened report by Jennifer Lee gives preliminary news of a recent survey of breeding Wandering Albatrosses Diomedea exulans on South Georgia (Islas Georgias del Sur)*.

“In early January a team of intrepid scientists and tourists embarked on a unique collaborative expedition to survey South Georgia’s outlying wandering albatross colonies.  The last island-wide survey took place in 2004 and showed a 30% decline since the survey in 1984.

The aim of the expedition was to visit all the known wandering albatross breeding sites outside of the large colonies at Bird Island and Annenkov Island.  The population at Bird Island is surveyed each year but it is important to periodically visit smaller colonies to understand the trends in abundance and distribution on South Georgia as a whole.  Logistic constraints meant it was not possible to visit Annenkov Island this year but a survey is planned for 2016.

Between January 9th and 20th 2015, scientists visited 25 sites from the Bay of Isles to Cape Disappointment.  Counts ranged from having 34 wandering albatross nests with eggs at Cape Alexandra, to just a single pair at Mollyhawk Island.  In the coming months the survey data from the South Georgia mainland will be combined with survey data from Bird Island and analysed more fully, but early indications are that populations are down approximately 15% from the survey in 2004.  The decline matches with the annual trends that have been seen on Bird Island and give a clear indication that more work to save the wandering albatross is needed.

A major component of the population decline of this great ocean nomad is likely to be due to mortality associated with fisheries.  Although in the last decade, no wandering albatross have been killed by vessels in South Georgia waters, the wide foraging range of this species means it is vulnerable to fisheries operating elsewhere in the South Atlantic and beyond.”

Wandering Albatross on Prion Island, photograph by Anton Wolfaardt

Click here to access the full news item and here for an earlier report in ACAP Latest News on the survey.

John Cooper, ACAP Information Officer, 15 May 2015

*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.

Harrison Pravder (Department of Biology, Washington University in St. Louis, USA) and colleagues have published in the Journal of the Hawai‘i Audubon Society 'Elepaio on the breeding phenology of the Wedge-tailed Shearwater Puffinus pacificus on the Hawaiian island of Oahu.

Although it has no abstract the full paper is available free-access on line. "The goal was to document the timing of egg laying and chick hatching, to obtain more up to date breeding phenology data, and to estimate the duration of incubation for the species at this breeding location."

Wedge-tailed Shearwater, photograph by Alan Burger

Reference:

Pravder, H., Prestridge, C. & Hyrenbach, K.D. 2015.  Wedge-tailed Shearwater breeding phenology at the Freeman Seabird Preserve, Oʻahu, Hawaiʻi.  'Elepaio 75: 17-21.

John Cooper, ACAP Information Officer, 14 May 2015

Madeleine Pott (Island Conservation, Santa Cruz, USA) and colleagues have published in the journal Biological Conservation on bait trials for rodent eradications on tropical islands.  One of the islands studied in the paper is Wake Atoll, a marginal breeding site for Laysan Albatrosses Phoebastria immutabilis (click here).

The paper’s abstract follows:

“Rodent eradications undertaken on tropical islands are more likely to fail than eradications undertaken at higher latitudes.  We report on 12 independent rodent eradication projects undertaken on tropical islands that utilized the results of an in situ bait availability study prior to eradication to inform, a priori, the bait application rate selected for the eradication.  These projects also monitored bait availability during the eradication.  The results from our analysis verified the utility of bait availability studies to future rodent eradication campaigns and confirmed the influence of two environmental factors that can affect bait availability over time: precipitation prior to the study and the abundance of land crabs at the study site.  Our findings should encourage eradication teams to conduct in-depth assessments of the targeted island prior to project implementation.  However, we acknowledge the limitations of such studies (two of the projects we reviewed failed and one removed only one of two rodent species present) and provide guidance on how to interpret the results from a bait availability study in planning an eradication.  Study design was inconsistent among the twelve cases we reviewed which limited our analysis.  We recommend a more standardized approach for measuring bait availability prior to eradication to provide more robust predictions of the rate at which bait availability will decrease during the eradication and to facilitate future comparisons among projects and islands.”

A breeding Laysan Albatross

With thanks to Mike Brooke for information.

Reference:

Pott, M., Wegmann, A.S., Griffiths, R., Samaniego-Herrera, A., Cuthbert, R.J., Brooke, M de L., Pitt, W.C., Berentsen, A.R., Holmes, N.D., Howald, G.R., Ramos-Rendón, K. & Russell, J.C. 2015.  Improving the odds: assessing bait availability before rodent eradications to aid in selecting bait application rates.  Biological Conservation 185: 27-35.

John Cooper, ACAP Information Officer, 13 May 2015

Delia Davies (Percy FitzPatrick Institute of African Ornithology, DST/NRF Centre of Excellence, University of Cape Town, South Africa) and colleagues have published in the on-line and open-access journal Avian Conservation and Ecology on attacks by introduced House Mice Mus musculus on Critically Endangered Tristan Albatross Diomedea dabbenena chicks on Gough Island.

The paper’s abstract follows:

“The critically endangered Tristan Albatross Diomedea dabbenena breeds almost exclusively on Gough Island, in the central South Atlantic, where breeding success is much lower than [of] other great albatrosses (Diomedea spp.) worldwide.  Most breeding failures occur during the chick-rearing stage, when other great albatrosses suffer few failures.  This unusual pattern of breeding failure is assumed to be largely due to predation by introduced house mice Mus musculus, but there have been few direct observations of mouse attacks.  We closely monitored the fates of 20 chicks in the Gonydale study colony (123 chicks in 2014) using motion-activated cameras to determine the causes of chick mortality.  Only 5 of 20 chicks survived to fledge, and of the 15 failures, 14 (93%) were due to mouse predation.  One mouse-wounded chick was killed by a Southern Giant Petrel Macronectes giganteus; the rest died outright from their wounds within 3.9 ± 1.2 days of the first attack.  Despite this high impact, most chicks were attacked by only 1-2 mice at once (maximum 9).  The remaining 103 chicks in the study colony were checked less frequently, but the timing of failures was broadly similar to the 20 closely monitored nests, and the presence of mouse wounds on other chicks strongly suggests that mice were responsible for most chick deaths.  Breeding success in the Gonydale study colony averages 28% from 2001 to 2014; far lower than the normal range of breeding success of Diomedea species occurring on islands free from introduced predators.  Island-wide breeding success fell below 10% for the first time in 2014, making it even more urgent to eradicate mice from Gough Island.”

Rob Ronconi holds a dying Tristan Albatross chick after a night of mouse attacks, photograph by Peter Ryan

With thanks to Ben Dilley for information.

Reference:

Davies, D., Dilley, B.J., Bond, A.L., Cuthbert, R.J. & Ryan, P.G. 2015. Trends and tactics of mouse predation on Tristan Albatross Diomedea dabbenena chicks at Gough Island, South Atlantic Ocean. Avian Conservation and Ecology 10(1): 5. http://dx.doi.org/10.5751/ACE-00738-100105.

John Cooper, ACAP Information Officer, 12 May 2015