An inquisitive Tristan Albatross painted by Lea Finke, from the photograph below by Michelle Risi

Recent news from the United Kingdom's Gough Island in the South Atlantic is that the Critically Endangered Tristan Albatross Diomedea dabbenena has had yet another poor breeding season due to the depredations by introduced House Mice.  Now a decision made earlier this week by the Board of Trustees of the UK’s Royal Society for the Protection of Birds (RSPB) has given the go ahead for the mouse eradication exercise on Gough next year.

In a blog yesterday, the RSPB writes:

“Over the last nine months, our team has continued to work at pace, planning to ensure we are in the best position possible, ready for this decision.  Almost the entire team of experts we had in place for 2020 (more than 60 people from four different continents) have made themselves available next year, and we have helicopters, ships and other contractors lined up ready to deploy.

We are acutely aware that the Covid-19 pandemic has introduced greater challenges to an already difficult operation.  While we cannot predict what the world will look like next year, we have factored as much mitigation as possible into our planning and we believe we can mobilise the teams safely to and through South Africa to ensure they can arrive on Gough to carry out the operational phase.

Our trustees, board members and programme team all agree that waiting until 2022 will not bring any better chances of success, that the restoration of Gough needs to happen as soon as possible and that we are in a position where we are confident we can see this through next year.”

Tristan Albatross, photograph by Michelle Risi

This year’s intended eradication by the RSPB’s Gough Island Restoration Programme (GIRP) was cancelled due to restrictions on international travel coming from the COVID-19 pandemic.  The RSPB is now hoping it can work round any continuing pandemic restrictions by delivering COVID-19-free field teams, and all the required equipment, to the island next year.  So is ACAP!

John Cooper, ACAP Information Officer, 27 December 2020

A Manx Shearwater among the flowers, photograph by Chris Perrins

Christopher Perrins (Department of Zoology, University of Oxford, UK) and colleagues have published open access in the annual journal Seabird on a census of Manx Shearwaters Puffinus puffinus on three islands off the coast of Wales.

The paper’s abstract follows:

“We present the results of a census of the Manx Shearwaters Puffinus puffinus nesting on the three Pembrokeshire islands of Skomer, Skokholm and Midland (formerly Middleholm), Pembrokeshire, undertaken in 2018. The breeding population estimates were largely in line with those made in 2011–2013, but differed markedly from 1998; this difference seems to be due to the different methods used in 1998 rather than any marked change in population size. Despite attempts to refine the estimation of response rate to call playback, the error of the population estimates remains large, illustrating the logistical and analytical challenges of making seabird censuses using call playback. Nonetheless, the population estimates are large and the spatial distribution of occupied burrows is consistent between censuses, and thus Wales may hold more than half of the world’s breeding population of Manx Shearwaters.”

Reference:

Perrins, C., Padget, O., O’Connell, M., Brown, R., Büche, B., Eagle, G., Roden, J., Stubbings,^, E. & Wood,^, M.J. 2019.  A census of breeding Manx Shearwaters Puffinus puffinus on the Pembrokeshire Islands of Skomer, Skokholm and Midland in 2018.  Seabird 32: 106-118.

John Cooper, ACAP Information Officer, 26 November 2020

 "The left pair is the Torishima-type Short-tailed Albatross, while the two on the right are the Senkaku-type Short-tailed Albatross. This is the first case of cryptic species found in an endangered bird species" - from the Endangered Species Research Facebook Page

Masaki Eda (Hokkaido University Museum, Sapporo, Japan) and colleagues have published open access in the journal Endangered Species Research on whether the Short-tailed Albatross Phoebastria albatrus should be two species, with consequent implications for the threatened status of the two cryptic populations.

The paper’s abstract follows:

“The occurrence of cryptic species within a threatened taxon is rare, but where they do occur, understanding species boundaries is essential for planning an effective conservation strategy. The short-tailed albatross Phoebastria albatrus is a Vulnerable seabird that mainly breeds on Torishima and the Senkaku Islands in the western North Pacific. Although it has been tacitly regarded as a single management unit with 2 breeding sites, the species is known to comprise 2 genetically separated populations (Senkaku-type and Torishima-type). However, morphological examination of birds from both populations has not been conducted owing to the difficulty in accessing the Senkaku Islands. In this study, we examined the morphological differences between immigrants from the Senkaku Islands to Torishima (Senkaku-type) and native birds on Torishima (Torishima-type) and found significant differences in morphological characteristics between the 2 bird types. In general, Torishima-type birds were larger than Senkaku-type birds, whereas Senkaku-type birds had relatively longer beaks. Based on the morphological differences found in this study as well as genetic and ecological differences revealed in previous studies, we believe that Senkaku- and Torishima-type birds should be classified as different cryptic species. To the best of our knowledge, this is the first case of cryptic species being identified in a threatened avian species.”

Reference:

Eda, M., Yamasaki, T., Izumi, H., Tomita, N., Konno, S.,Konno, M., Murakami, H. & Sato, F. 2020.  Cryptic species in a Vulnerable seabird: short-tailed albatross consists of two species.  Endangered Species Research doi.org/10.3354/esr01078 doi.org/10.3354/esr01078.

John Cooper, ACAP Information Officer, 25 November 2020

A Tristan Albatross chick, photograph by Tom McSherry

It has been another poor breeding season for the beleaguered Tristan Albatross Diomedea dabbenena on the United Kingdom's Gough Island in the South Atlantic.  Last month the outgoing and incoming field teams working for the Gough Island Restoration Programme (GIRP) joined up to undertake the annual count of chicks of the near-endemic and Critically Endangered species across the whole island.  A total of 569 chicks was counted that had survived - so far – the mainly winter depredations of the introduced House Mouse.  A few more chicks would be expected to die before fledging occurs around year end.

Ready for the count: the outgoing and incoming GIRP field teams at the helipad on Gough Island

The October count compares to the 1528 nests containing incubating birds counted back in January.  Based on these totals overall breeding success is 37.2%.  This means that only a little over a third of the breeding pairs will have successfully fledged a chick by season end.  GIRP reports that breeding success (as has been usual over two decades of study) varied across the island, with some count areas being as low as 18.7%, with the highest at 60.9%.  The overall average, once again, compares extremely poorly with those of other great albatrosses of the genus Diomedea on rodent-free islands - where a breeding success of 65-70% (around two thirds) is normal.

Attacked by mice overnight, this study colony Tristan Albatross chick died soon afterwards, photograph by Karen Bourgeois & Sylvain Dromzee

Last year’s plan to eradicate the island’s mice had to be cancelled due to restrictions on international travel as a consequence of the COVID-19 pandemic.  A decision is awaited by GIRP as to whether another attempt will be made in 2021 (click here).

John Cooper, ACAP Information Officer, 24 November 2020