Dario Capizzi (Latium Region—Regional Park Agency, Rome, Italy) and colleagues have published in a book on problematic wildlife showing that breeding success of Scopoli’s Calonectris diomedea and Yelkouan Puffinus yelkouan Shearwaters increases after eradication of Black Rats Rattus rattus on Italian islands in the Mediterranean.  The latter species has been identified as a potential candidate for listing within the Agreement.

The chapter’s abstract follows

“The black rat (Rattus rattus) is thought to be the most widespread mammal on Mediterranean islands.  In recent years, many field studies have documented its detrimental impact on native species, communities and ecosystems.  In order to restore island ecosystems by eliminating the impacts of black rat, several projects have been planned and implemented during the last 15 years on Italian islands.  Although these projects were specifically aimed at protecting nesting shearwaters Calonectris diomedea and Puffinus yelkouan from rat predation, they were also planned in order to provide benefits to other island ecosystem components, species and communities.  Rats were eradicated from small islands (about 1 ha of surface) to very large islands (over 1000 ha, i.e. Montecristo).  Monitoring programmes showed that shearwater reproductive success increased after rat eradication.  During these years, we obtained data on different aspects related to the problem of rat impact and control on islands: (1) rat impact on target species; (2) benefits for native species from rat removal; (3) field techniques and bait delivery methods; (4) impact of rodenticides on non-target species; (5) rat abundance, home range and movements and (6) rat reinvasion after eradication.  Furthermore, we developed a model aimed at identifying priority islands where rat eradication should be carried out, and/or establish recommended actions.”

Scopoli's Shearwater fledgling 

Reference:

Capizzi, D., Baccetti, N. & Sposimo, P. 2016. Fifteen years of rat eradication on Italian islands.  In: Angelici, F.M. (Ed.).  Problematic Wildlife.  A Cross-Disciplinary Approach.  Berlin: Springer International Publishing.  pp 205-227.

John Cooper, ACAP Information Officer, 27 December 2015

Paco Bustamante (Littoral Environnement et Sociétés, Université de la Rochelle, France) and colleagues have published in the journal Environmental Research on mercury levels in Wandering Albatrosses Diomedea exulans.

The paper’s abstract follows

“Hg can affect physiology of seabirds and ultimately their demography, particularly if they are top consumers.  In the present study, body feathers of >200 wandering albatrosses from Possession Island in the Crozet archipelago were used to explore the potential demographic effects of the long-term exposure to Hg on an apex predator.  Variations of Hg with sex, age class, foraging habitat (inferred from δ13C values), and feeding habits (inferred from δ15N values) were examined as well as the influence of Hg on current breeding output, long-term fecundity and survival.  Wandering albatrosses displayed among the highest Hg feather concentrations reported for seabirds, ranging from 5.9 to 95 µg g−1, as a consequence of their high trophic position (δ15N values).  These concentrations fall within the same range of those of other wandering albatross populations from subantarctic sites, suggesting that this species has similar exposure to Hg all around the Southern Ocean.  In both immature and adult albatrosses, females had higher Hg concentrations than males (28 vs. 20 µg g−1dw on average, respectively), probably as a consequence of females foraging at lower latitudes than males (δ13C values).  Hg concentrations were higher in immature than in adult birds, and they remained fairly constant across a wide range of ages in adults.  Such high levels in immature individuals question (i) the frequency of moult in young birds, (ii) the efficiency of Hg detoxification processes in immatures compared to adults, and (iii) importantly the potential detrimental effects of Hg in early life.  Despite very high Hg concentrations in their feathers, neither effects on adults' breeding probability, hatching failure and fledgling failure, nor on adults' survival rate were detected, suggesting that long-term bioaccumulated Hg was not under a chemical form leading to deleterious effects on reproductive parameters in adult individuals.”

Wandering Albatross incubating, photograph by Linda Clokie

Reference:

Bustamante, P., Carravieri, A., Goutte, A., Barbraud, C., Delord, K., Chastel, O., Weimerskirch, H. & Cherel, Y. 2016.  High feather mercury concentrations in the wandering albatross are related to sex, breeding status and trophic ecology with no demographic consequences.  Environmental Research 144A: 1-10.

John Cooper, ACAP Information Officer, 26 December 2015

Michelle Kappes (Department of Fisheries and Wildlife, Oregon State University, Corvallis, USA) and colleagues have published in the journal Movement Ecology on foraging patterns of Laysan Phoebastria immutabilis and Black-footed P. nigripes Albatrosses.

The paper’s abstract follows:

“Background: The spatiotemporal distribution of animals is dependent on a suite of factors, including the distribution of resources, interactions within and between species, physiological limitations, and requirements for reproduction, dispersal, or migration. During breeding, reproductive constraints play a major role in the distribution and behavior of central place foragers, such as pelagic seabirds.  We examined the foraging behavior and marine habitat selection of Laysan (Phoebastria immutabilis) and black-footed (P. nigripes) albatrosses throughout their eight month breeding cycle at Tern Island, Northwest Hawaiian Islands to evaluate how variable constraints of breeding influenced habitat availability and foraging decisions.  We used satellite tracking and light-based geolocation to determine foraging locations of individuals, and applied a biologically realistic null usage model to generate control locations and model habitat preference under a case–control design.  Remotely sensed oceanographic data were used to characterize albatross habitats in the North Pacific.

Results: Individuals of both species ranged significantly farther and for longer durations during incubation and chick-rearing compared to the brooding period.  Interspecific segregation of core foraging areas was observed during incubation and chick-rearing, but not during brooding.  At-sea activity patterns were most similar between species during brooding; neither species altered foraging effort to compensate for presumed low prey availability and high energy demands during this stage.  Habitat selection during long-ranging movements was most strongly associated with sea surface temperature for both species, with a preference for cooler ocean temperatures compared to overall availability.  During brooding, lower explanatory power of habitat models was likely related to the narrow range of ocean temperatures available for selection.

Conclusions: Laysan and black-footed albatrosses differ from other albatross species in that they breed in an oligotrophic marine environment.  During incubation and chick-rearing, they travel to cooler, more productive waters, but are restricted to the low-productivity environment near the colony during brooding, when energy requirements are greatest.  Compared to other albatross species, Laysan and black-footed albatrosses spend a greater proportion of time in flight when foraging, especially during the brooding period; this strategy may be adaptive for locating dispersed prey in an oligotrophic environment.”

Laysan and Black-footed Albatrosses in flight at Midway Atoll, photograph by Eric Vanderwerf

Reference:

Kappes, M.A., Shaffer, S.A., Tremblay, Y., Foley, D.G., Palacios, D.M., Bograd, S.J. & Costa, D.P. 2015.  Reproductive constraints influence habitat accessibility, segregation, and preference of sympatric albatross species.  Movement Ecology 3: 34.  10.1186/s40462-015-0063-4.

John Cooper, ACAP Information Officer, 25 December 2015

ACAP Secretariat, 24 December 2015