Felipe Ceia (Marine and Environmental Research Centre, University of Coimbra, Portugal) and colleagues have published in the journal Rapid Communications in Mass Spectrometry on stable isotope ratios in the blood of tracked  Wandering Albatrosses Diomedea exulans.

The paper’s abstract follows:

“Rationale

The main limitation of isotopic tracking for inferring distribution is the lack of detailed reference maps of the isotopic landscape (i.e. isoscapes) in the marine environment.  Here, we attempt to map the marine δ¹³C isoscape for the southwestern sector of the Atlantic Ocean, and assess any temporal variation using the wandering albatross as a model species.

Methods

Tracking data and blood and diet samples were collected monthly from wandering albatrosses rearing chicks at Bird Island, South Georgia, during the austral winter between May and October 2009.  The δ¹³C and δ¹⁵N values were measured by mass spectrometry in plasma and blood cells, and related to highly accurate data on individual movements and feeding activity obtained using three types of device: GPS, activity (immersion) loggers and stomach temperature probes.

Results

The tracked birds foraged in waters to the north or northwest of South Georgia, including the Patagonian shelf-break, as far as 2000 km from the colony.  The foraging region encompassed the two main fronts in the Southern Ocean (Polar and Subantarctic fronts).  The δ¹³C values varied by only 2.1 ‰ in plasma and 2.5 ‰ in blood cells, and no relationships were found between the δ¹³C values in plasma and the mean latitude or longitude of landings or feeding events of each individual.

Conclusions

The failure to distinguish a major biogeographic gradient in δ¹³C values suggest that these values in the south Atlantic Ocean are fairly homogeneous.  There was no substantial variation among months in either the δ¹³C or the δ¹⁵N values of plasma or blood cells of tracked birds.  As birds did not show a significant change in diet composition or foraging areas during the study period, these results provide no evidence for major temporal variation in stable isotope ratios in consumer tissues, or in the regional marine isoscape in the austral winter of 2009.”

Wandering Albatross at sea, photograph by John Chardine

Reference:

Ceia, F.R., Ramos, J.A., Phillips, R.A., Cherel, Y., Jones, D.C., Vieira, R.P. & Xavier, J.C. 2015.  Analysis of stable isotope ratios in blood of tracked wandering albatrosses fails to distinguish a δ13C gradient within their winter foraging areas in the southwest Atlantic Ocean.  Rapid Communications in Mass Spectrometry 29: 2328-2336.

John Cooper, ACAP Information Officer, 15 November 2015

Ben Dilley (Percy FitzPatrick Institute of African Ornithology, DST/NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa) has filmed introduced House Mice Mus musculus attacking chicks of the Critically Endangered Tristan Albatross Diomedea dabbenena and Endangered Atlantic Petrel Pterodroma incerta on Gough Island in the South Atlantic.

Rob Ronconi holds a dying Tristan Albatross attacked on its rump by mice, photograph by Peter Ryan

View the video clips by clicking on the species’ names here:

Tristan Albatross

Atlantic Petrel

A picture truly tells a thousand words.

John Cooper, ACAP Information Officer, 14 November 2015

Ben Dilley and colleagues (Percy FitzPatrick Institute of African Ornithology, DST/NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa) report in the journal Antarctic Science on attacks on albatross chicks by introduced House Mice Mus musculus on Marion Island.

The paper’s abstract follows

“House mice (Mus musculus L.) were introduced to sub-Antarctic Marion Island more than two centuries ago, and have been the only introduced mammal on the island since 1991 when feral cats were eradicated.  The first mouse-injured wandering albatross (Diomedea exulans L.) chick was found in 2003 and since then attacks have continued at a low level affecting <1% of the population.  In 2009, the first ‘scalpings’ were detected; sooty albatross (Phoebetria fusca Hilsenberg) fledglings were found with raw wounds on the nape.  In 2015, mice attacked large chicks of all three albatross species that fledge in autumn: grey-headed (Thalassarche chrysostoma Forster) (at least 102 wounded chicks; 4.6% of fledglings), sooty (n=45, 4.3%) and light-mantled albatross (P. palpebrata Forster) (n=1, 4%).  Filming at night confirmed that mice were responsible for wounds.  Attacks started independently in small pockets all around the island’s 70 km coastline, separated by distances hundreds of times greater than mouse home ranges.  The widespread nature of mouse attacks in 2015 on large, well-feathered chicks is alarming and highlights not only Marion Island as a priority island for mouse eradication but also that mice alone may significantly affect threatened seabird species.”

 Scalped Grey-headed Abatross chicks, photograph by Ben Dilley

Wandering Albatross chick being attacked by mice, photographs by Stefan Schoombie

Click here for a popular account on scalping by mice at Marion Island.

With thanks to Susan Mvungi, Niven Library, University of Cape Town for information.

Reference:

Dilley, B.J., Schoombie, S., Schoombie, J. & Ryan, P.G. 2015.  ‘Scalping’ of albatross fledglings by introduced mice spreads rapidly at Marion Island.  Antarctic Science doi.org/10.1017/S0954102015000486.

John Cooper, ACAP Information Officer, 13 November 2015

Barry Baker (Latitude 42 Environmental Consultants, Kettering, Tasmania, Australia) and colleagues have submitted a draft report to the Conservation Services Programme (CSP) of NewZealand’s Department of Conservation that gives the results of aerial surveys of White-capped Albatrosses Thalassarche steadi on the Auckland Islands south of New Zealand.

The report’s Executive Summary follows:

“White-capped albatrosses Thalassarche steadi are endemic to New Zealand, breeding on Disappointment Island, Adams Island and Auckland Island in the Auckland Island group, and Bollons Island (50-100 pairs) in the Antipodes Island Group (Gales, 1998).  Previous population estimates that we have developed (Baker et al. 2014) show that most (95%) of the global population breeds on Disappointment Island, an area where access is restricted to maintain environmental values at the site.

Between 2006/07 and 2014/15 (hereinafter 2006 and 2014, respectively) we undertook repeated population censuses of the white-capped albatrosses breeding in the Auckland Islands using aerial photography.  These population censuses were carried out in either December or January each year to estimate population size and track population trends.  Our measure of population size was ‘Annual breeding pairs’, defined as any pair of albatrosses that lays an egg in the breeding season of interest.  All other birds in colonies were assessed as  ‘Loafers’, defined as birds present in a colony but which do not appear to be associated with an active nest at the time of observation.

In 2014 we estimated that there were 96,864 (95%CI 96,242 — 97,486), 4,741 (4,603 — 4,879) and 193 (165— 221) annual breeding pairs at Disappointment Island, South West Cape and Adams Island, respectively, in 2014, based on the raw counts, giving a total for these sites of 101,798 (101,160 — 102,436) breeding pairs.  Based on an assessment of 15 aerial close-up photos, 5.8% of birds in the colonies were loafers.  After adjusting the raw counts to account for loafing birds, we estimate that there were 95,894 annual breeding pairs in the Auckland Islands in 2014.  Previous annual counts have ranged from 73,838 to 116,025 annual breeding pairs (mean 90,781 annual breeding pairs).

Ground counts undertaken by Thompson et al. (2015) in January 2015, a few days before the 2014 aerial counts were undertaken, showed that of 1,127 birds sitting on nests, 909 (81%) were incubating eggs and 218 birds (19%) were sitting on empty nests.  These data can be compared with ground counts of nests taken earlier in the breeding season (December) in 2008 that showed that 93.5% contained eggs and only 6.5% were empty.  Aerial counts undertaken earlier in the breeding season are likely to provide a more accurate estimate of annual breeding pairs as nest failures occur progressively throughout the breeding season once egg laying has been completed.  Ground-truthing data assessing the proportion of birds sitting on empty nests will not reliably provide a correction factor relevant to determining annual breeding pairs, as a bird sitting on an empty nest may have laid and subsequently lost its egg, may be yet to lay, or simply be a non-breeding loafer.

Count data over nine years show strong inter-annual fluctuations, a characteristic we have observed for many other seabird species.  This variability would encompass counting error, the presence of non-breeding birds during counts, environmental stochasticity and other unknown variables that are not easily quantified.  Trend analysis of nine years of counts using regression splines showed no clear evidence for systematic increase or decline over the nine years of the study.  Given this we do not have sufficient evidence to reject the null hypothesis of no systematic trend in the total population.  The trend should be considered to be uncertain; however, the null hypothesis of a stable population remains tenable and is probably a reasonable interpretation.”

With thanks to Barry Baker for information.

White-capped Albatross, photograph by Graham Parker

Reference:

Baker, G.B., Jensz, K., Cunningham, R., Holdsworth, M. & Chilvers, B.L. 2015.  White-capped Albatross Aerial Survey 2015 Draft Final Report.  Report prepared for Department of Conservation Contract 4625.  [Kettering]: Latitude 42 Environmental Consultants.  20 pp.

John Cooper, ACAP Information Officer, 12 November 2015