Rachael Alderman (Department of Primary Industries, Parks, Water and Environment, Hobart, Australia) writes in the latest on-line number of the Australian Antarctic Magazine on deaths from non-target poisoning, especially of ACAP-listed Northern Giant Petrels Macronectes halli, caused by the Macquarie Island Pest Eradication Project (MIPEP).

She describes “the impact of poison baiting on giant petrels, during the rabbit, rat and mouse eradication project on the island.  A 30% decline in the population of both northern and southern giant petrels has been observed, but there is optimism that populations will bounce back.”

Of a total of 2500 birds known to have died over the 2010 and 2011 bait drops, 760 were giant petrels with the ratio between Northerns and Southerns M. giganteus being 40:1.  Eighty percent of the giant petrels found dead were males, reflecting their more terrestrial feeding habits in comparison to females which feed more at sea.  The similar decline in numbers of Southern Giant Petrels, but with far fewer corpses found on the island, is suggested to be due to birds dying at sea.

Meanwhile MIPEP Manager Keith Springer reports to ACAP from Macca on the ongoing searches for any remaining rabbits and rodents on the island: “Feb[ruary] will be our last month for hunting fieldwork on Macquarie (where I am currently spending the summer) – with any luck we should be able to announce it as done at the end of March”.

Northern Giant Petrel, photographed by Marienne de Villiers

Click here to read the latest MIPEP Blog for last month on changes to Macca’s vegetation by Field Assistant Lachlan Francis.

Click on MIPEP to access 17 news stories in ACAP Latest News posted over the last three years on progress with the pest eradication project on Macquarie Island.

Reference:

Alderman, R. 2013.  Managing the cost of pest eradication.  Australian Antarctic Magazine 25: 18-19.

John Cooper, ACAP Information Officer, 25 January 2014

Isabel Afán (Estación Biológica de Doñana, Sevilla, Spain) and colleagues have published in the journal Marine Biology on differences in the foraging areas of sympatric Cory’s Calonectris borealis and Scopoli’s C. diomedea Shearwaters during chick-rearing in the Mediterranean’s Chafarinas Archipelago.

The paper’s abstract follows:

“As central-place foragers, pelagic seabirds are constrained by spatiotemporal heterogeneity to find productive marine areas and compete for prey.  We analysed 97 foraging trips to study the movement and oceanographic characteristics of foraging habitats of two different—yet closely related—species of shearwaters (Scopoli’s shearwater Calonectris diomedea and Cory’s shearwater C. borealis) breeding in sympatry in the Mediterranean.  We combined various methodological approaches (GPS-tracking, species distribution modelling and stable isotope analysis) to explore the foraging strategies of these two species.  Isotopic results suggested that trophic habits of both shearwater species were similar, mainly based on pelagic fish consumption.  Foraging areas of both species were characterized by shallow waters near the colony.  Both shearwater species exploited persistent productive marine areas.  The foraging areas of the two species broadly overlapped during the incubation period, but during chick-rearing period, Scopoli’s shearwaters apparently foraged in different areas than Cory’s shearwaters.”

Cory's Shearwater, photograph by Paulo Catry

Reference:

Afán, I., Navarro, J., Cardador, L., Ramírez, F., Kato, A., Rodríguez, B., Ropert-Coudert, Y. & Forero, M.G. 2013.  Foraging movements and habitat niche of two closely related seabirds breeding in sympatry.  Marine Biology DOI 10.1007/s00227-013-2368-4.

John Cooper, ACAP Information Officer, 24 January 2013

The 2013 IUCN Red List update was published in November.  Seabird species accounts may now be viewed on the BirdLife Data Zone and IUCN Red List website.

In preparation for the 2014 Red List update, BirdLife International has extended an invitation to participate in the forum process to discuss proposed revisions to the global threat status (IUCN Red List category of extinction risk) for selected species, including ACAP-listed albatrosses, petrels and shearwaters and other seabirds.  Visit the seabird forum to read of species under review and to post your own comments on proposals.

“The initial deadline for contributions is 10 February 2014, when we will assess the contributions made.  We will then post up a draft list of preliminary decisions and you will have two more weeks to comment further before final decisions are posted.  The new and revised species assessments and updated factsheets will be published on the BirdLife website and incorporated into the 2014 IUCN Red List, currently scheduled for release in June.”

Grey Petrel: proposed for review, photograph by Peter Ryan

To propose additional species for review post a comment on the relevant ‘Suggestions for new topics’ discussion, or email This email address is being protected from spambots. You need JavaScript enabled to view it.; in either case giving details of population/range size or trend estimates that may require revision.

Assessments of the threat status of newly-defined non-passerine species will be undertaken this year, and Red List assessments for these species will be published in the 2014 Red List update.  The vast majority of topics for the 2014 update have now been posted on the forum website, but a few further discussions will be added over the coming days and weeks, so keep checking back for updates.

Read more on the 2013 changes here.

With thanks to Joe Taylor for information.

John Cooper, ACAP Information Officer, 23 January 2014

Ewan Wakefield (British Antarctic Survey, Cambridge, UK) and colleagues write in the journal Proceedings of the Royal Society B on what regulates populations of Black-browed Albatrosses Thalassarche melanophris.

The paper’s abstract follows:

“Animal populations are frequently limited by the availability of food or of habitat.  In central-place foragers, the cost of accessing these resources is distance-dependent rather than uniform in space.  However, in seabirds, a widely studied exemplar of this paradigm, empirical population models have hitherto ignored this cost.  In part, this is because non-independence among colonies makes it difficult to define population units.  Here, we model the effects of both resource availability and accessibility on populations of a wide-ranging, pelagic seabird, the black-browed albatross Thalassarche melanophris.  Adopting a multi-scale approach, we define regional populations objectively as spatial clusters of colonies.  We consider two readily quantifiable proxies of resource availability: the extent of neritic waters (the preferred foraging habitat) and net primary production (NPP).  We show that the size of regional albatross populations has a strong dependence, after weighting for accessibility, on habitat availability and to a lesser extent, NPP.  Our results provide indirect support for the hypothesis that seabird populations are regulated from the bottom-up by food availability during the breeding season, and also suggest that the spatio-temporal predictability of food may be limiting.  Moreover, we demonstrate a straightforward, widely applicable method for estimating resource limitation in populations of central-place foragers.”

Black-browed Albatross in flight, photograph by Juan Pablo Seco Pon

With thanks to Richard Phillips for information.

Reference:

Wakefield, E.D., Phillips, R.A. & Matthiopoulos, J. 2014.  Habitat-mediated population limitation in a colonial central-place forager: the sky is not the limit for the black-browed albatross.  Proceedings of the Royal Society B.

John Cooper, ACAP Information Officer, 22 January 2014