A burrow nest of a Subantarctic Rayadito in an active Grey-headed Albatross nest, Gonzalo Island, Islas Diego Ramírez, summer 2020/21; photograph by Maximiliano Daigre

Chile’s Diego Ramírez Islands 100 km south-west of Cape Horn, are important breeding sites for three ACAP-listed species: Black-browed Thalassarche melanophris and Grey-headed T. chrysostoma Albatrosses and Southern Giant Petrel Macronectes giganteus.

The Subantarctic Rayadito; photograph by Carlos Garcés Letelier

A group of Chilean researchers visiting Gonzalo Island, Diego Ramírez has discovered and described a new landbird species, the Subantarctic Rayadito Aphrastura subantarctica, in the journal Scientific Reports.  Rayaditos in the genus Aphrastura (Passeriformes: Furnariidae - oven bird family), are terrestrial birds endemic to south-western South America and until now were known only by two species.  These are the Thorn-tailed Rayadito A. spinicauda inhabiting the temperate forests of Chile and parts of Argentina, and the Masafuera Rayadito A. masafuerae, strongly associated with the tree fern forests of oceanic Alejandro Selkirk Island, 835 km off continental Chile.

Grey-headed Albatrosses breeding among tussock clumps on Diego Ramírez; photograph by Carlos Garcés Letelier

The presence of a rayadito species was first recorded on Diego Ramírez on an ornithological expedition by the late Roberto Schlatter and Guillermo Riveros, 41 years ago in the austral summer of 1980/81 (click here). After this first encounter, Schlatter was concerned that he was dealing with a species different from the rest of the rayaditos.  This was particularly because Diego Ramírez's rayadito lived among tussock grass Poa flabellata and nested in burrows in the ground, in contrast to the continental rayadito that inhabits forests.

The new paper and its supplementary information also highlight the relationship of the Subantarctic Rayadito with the islands’ seabirds.  We have been recording rayaditos on Diego Ramírez for more than a decade, slowly beginning to understand their relationship with albatrosses.  For example, in high densities of breeding Black-browed Albatrosses, the Subantarctic Rayadito is generally found linked to the tussock that surrounds albatross nests, moving with short flights between the plants.

One of the curiosities that has emerged is that a Subantarctic Rayadito was recorded breeding in a burrow in the side of an active Grey-headed Albatross nest.  The new rayadito species commonly breeds among tussock pedestals and rocky crevices.  The presence of Grey-headed Albatrosses, which breed in lower densities among tussock plants, in comparison with the relatively bare habitat of breeding Black-browed Albatrosses, is thus ideal for Subantarctic Rayadito nests.  Tussock is also key for the foraging of rayaditos, a small bird that searches for invertebrates caught among the tussock and even in the entrances of Blue Petrel Halobaena caerulea burrows.  The tusock habitat among albatrosses is also thought to offer protection to aerial predators, such as the Chilean Skua Stercorarius chilensis and Striated Caracara Phalcoboenus australis.

Covered in tussock: the Diego Ramírez Islands with a view of Bartolomé from Gonzalo, the two main islands of the Archipelago in the Drake Passage; photograph by Cristián G. Suazo

Fortunately, Diego Ramírez is free of invasive species that could affect both its land and seabirds. The presence of a new sub-Antarctic bird species calls attention to the fragility of and need to watch over one of the last living treasures that we still have.

Reference:

Rozzi, R., Quilodrán, C.S., Botero-Delgadillo, E., Napolitano, C., Torres-Mura, J.C., Barroso, O., Crego, R.D., Bravo, C., Ippi, S., Quirici, V., Mackenzie, R., Suazo, C.G., Rivero-de-Aguilar, J., Goffinet, B., Kempenaers,  B., Poulin, E. & Vásquez, R.A. 2022.  The Subantarctic Rayadito (Aphrastura subantarctica), a new bird species on the southernmost islands of the Americas.  [and supplementary information].  Scientific Reports 12, 13957.  doi.org/10.1038/s41598-022-17985-4.

Cristián G. Suazo, Puerto Montt, Chile, 15 September 2022

Image credit: Campbell Albatross off North Cape, NZ; photograph by Kirk Zufelt

ACAP would like to advise applications for the 2022 Secondment Programme are closing soon. 

Progress reports from previous and ongoing secondments (including the examples below) can be found in the Advisory Committee Information Papers from previous meetings, here. Proposals should aspire to foster cross-Party collaboration, knowledge-sharing and capacity-building within Parties. Applicants are encouraged to develop proposals that account for any ongoing practical challenges and limitations associated with the COVID-19 pandemic.

Previous successful proposals have included:

• Habitat selection of the Black-browed Albatross (Thalassarche melanophris) in the South-West Atlantic: importance of marine fronts and fishing activity 
• Connecting knowledge, people and countries: Advancing in outreach, understanding of threats and mitigation measures for the conservation of Pink-footed Shearwater (Ardenna creatopus) throughout its cycle. 

Applicants are advised to focus proposals on tasks contained within the work programmes of the Advisory Committee (Annex 4, MoP7 Report) and Secretariat (see Annex 2, MoP7 Report). 

Applications will only be accepted from ACAP Parties.  Applicants are encouraged to contact the Working Group Convenors, the Advisory Committee Chair or Vice-chair, or the This email address is being protected from spambots. You need JavaScript enabled to view it. to help identify ACAP priority areas for their proposal. Completed applications are to be submitted to relevant ACAP National Contact Points, who will then forward them to the ACAP Secretariat.

Applications must be received by the ACAP Secretariat by close of business on Monday, 26 September 2022. Applicants will be advised of the outcome of their application by Tuesday, 8 November 2022.

Click here for more information, including application criteria, and the application form (also available in French and Spanish).

Posted 14 September 2022 

Newell’s Shearwater; photograph by Lindsay Young

André Raine (Archipelago Research and Conservation, Hanapepe, Kaua‘I, Hawaii, USA) and colleagues have published in the journal Waterbirds on nest-site aspects of the Endangered Hawaiian Petrel Pterodroma sandwichensis and the Critically Endangered Newell's Shearwater Puffinus newelli on the Hawaiian island of Kauai.

The paper’s abstract follows:

“The nest site characteristics of two endangered seabird species – the Hawaiian Petrel Pterodroma sandwichensis and Newell's Shearwater Puffinus newelli – on Kaua‘i were considered.  Burrows of both species were predominantly found under tree roots or small caves on steep slopes and were associated with native plants, both in the canopy (particularly Metrosideros polymorpha) and the understory (particularly Dicranopteris linearis).  There were, however, marked differences between the two species.  Petrels were found at higher elevations with a shorter, patchy canopy and more open understory.  Models using microhabitat variables were better able to classify burrows than those using landscape topographic metrics, suggesting that metrics describing the immediate area around the burrow are more important to burrow selection.   A comparative model indicated that elevation and maximum vegetation height were the strongest variables in classifying between the two species.  Understanding microhabitat needs for these species is important for locating new colonies and for the successful implementation of management actions such as colony creation through social attraction.  Furthermore, wih the spread of Rapid’Ōhi’a Death canker disease Ceratocystis huliohia on Kaua‘i, the heavy reliance by both species on forest dominated by M. polymorpha (the tree killed by this disease) should be of increasing consideration for conservation efforts targeting these species.”

A Hawaiian Petrel chick in its burrow; photograph by André Raine

Reference:

Raine, A.F., Driskill, S., Rothe, J. & Vynne. M. 2021.  Nest site characteristics of two endangered seabirds in montane wet forests on the island of Kaua‘i, Hawai‘i, USA.  Waterbirds 44: 472-482.

John Cooper, ACAP News Correspondent, 13 September 2022

A Manx Shearwater amongst flowers; photograph by Chris Perrins

Clare L. Alley (School of Animal, Rural and Environmental Sciences, Nottingham Trent University, Nottinghamshire, United Kingdom) and colleagues have published open access in Seabird on the prevalence of plastic ingestion by Manx Shearwaters on Skomer Island, Wales.

ACAP has recently announced “Plastic Pollution” as the 2023 theme for World Albatross Day, marked annually on June 19. The Manx Shearwater is not an ACAP-listed species, however it, along with many albatrosses, petrels, shearwaters and other seabirds, are foraging in waters increasingly polluted with plastic. 

Two new albatross species will be used to feature the theme for next year’s World Albatross Day, with artworks, posters, infographics and a music video.  These will be the globally Endangered Northern Royal Albatross D. sanfordi, endemic to New Zealand, and the abundant and widespread Black-browed Albatross Thalassarche melanophris.  In addition, coverage will be given to last year’s featured species, the Black-footed Phoebastria nigripes and Laysan P. immutabilis Albatrosses of the North Pacific, which ingest more plastic than do the southern hemisphere species.

More information on next year's World Albatross Day and its theme of "Plastic Pollution" can be found at the ACAP website, here. 

The paper's abstract is as follows:

“Plastic debris is ubiquitous in the marine environment, and seabirds are among the most impacted marine vertebrates. Plastic ingestion was investigated in an internationally-important breeding population of Manx Shearwaters Puffinus puffinus on Skomer Island, Wales in 2018–19. Opportunistic necropsies were carried out on a total of 34 birds to collect contents of the gastrointestinal tract: 13 adults in April – July 2018 and 12 fledglings during September 2019, and a further nine opportunistic necropsies carried out from adults in July – September 2018. The presence, quantity, size and colour of plastic in the gastrointestinal tract was investigated. Plastic was found in 71% of stomach contents (68% of adults, 75% of fledglings). Adults were found to have larger plastic pieces in their gastrointestinal tract than fledglings, and lighter birds had larger pieces of plastic in their tracts than heavier birds. This study shows that Manx Shearwaters on Skomer Island are vulnerable to plastic ingestion, and that adults are likely to pass plastic to their chicks.”

REFERENCE:

Alley, C.L., Arkless, S., Ames, E., Abrahams, M., Gentle, L.K. and Wood, M.J. 2022. Plastic ingestion in adult and fledgling Manx Shearwaters Puffinus puffinus on Skomer Island, Wales. Seabird: 34.http://www.seabirdgroup.org.uk/seabird-34

Posted 12 September 2022