Timothee Zidat (Université de Montpellier, France) and colleagues write in the Zoological Journal of the Linnean Society on assortative mating in sympatrically breeding Cory’s Calonectris borealis and Scopoli's C. diomedea Shearwaters.

The paper’s abstract follows:

“Reproductive isolation of avian species often extensively relies on mate choice. Several bird species have recently been shown to use chemical cues in mate choice, in addition to the well-studied visual and acoustic signals. The two former European subspecies of Cory’s shearwater have been recently afforded species status as Calonectris borealis and C. diomedea, but their level of reproductive isolation has not fully been evaluated and one previous study suggested that their nuclear genome is undifferentiated. The species differ in chemical labels (volatile compounds in uropygial gland secretions) in allopatry, but whether these differences are maintained in sympatry or not remains unclear. We sampled both species in a mixed colony in the Chafarinas Islands in order to test whether their nuclear genomes are truly undifferentiated and to study their level of reproductive isolation in sympatry. We also tested whether the chemical differences in uropygial secretions observed in allopatric populations are maintained in sympatry or not. We established a clear divergence in nuclear genome between these species, suggesting efficient reproductive isolation mechanisms, and found evidence for assortative mating. We also found that chemical labels remain distinct in sympatry, suggesting their divergence is not purely due to environmental effects.”

Cory's Shearwater, photograph by Paulo Catry

Reference:

Zidat, T., Dell’Ariccia, G., Gabirot, M., Sourrouille, P., Buatois, B. Celerier, A. Bonadonna, F. & Crochet, P.-A. 2017.  Reproductive isolation maintains distinct genotypes, phenotypes and chemical signatures in mixed colonies of the two European Calonectris shearwaters (Procellariiformes: Procellariidae).  Zoological Journal of the Linnean Society.  doi.org/10.1093/zoolinnean/zlx002.

John Cooper, ACAP Information Officer, 12 June 2017

BirdLife International uses its Globally Threatened Bird Forums to update the Red List for birds on behalf of IUCN (International Union for Conservation of Nature).  In preparation for the 2017 update, BirdLife has invited participation in the forum process to discuss proposed revisions to the global threat status (IUCN Red List category of extinction risk) for selected species.

Three ACAP-listed albatrosses and petrels have been included in the Threatened Seabird Forum for consideration in the June round with details regarding the proposed changes:

Antipodean Albatross Diomedea antipodensis: proposed for up-listing to Endangered from Vulnerable.

Black-browed Albatross Diomedea melanophris: proposed for down-listing from Near Threatened to Least Concern.

Westland Petrel Procellaria westlandica: currently Vulnerable; request for information following Tropical Storm Ita causing damage to the species’ sole breeding site in 2014.

Antipodes Albatross (subspecies gibsoni) on Adams Island, Auckland Islands, photograph by Colin O'Donnell

“The initial deadline for contributions is 17 July 2017, when we will assess the contributions made. We will then post up a draft list of preliminary proposals and there will be two more weeks to comment further before final recommendations to IUCN are collated. The new and revised species assessments and updated factsheets will be published on the BirdLife website and incorporated into the 2017 IUCN Red List, currently scheduled for release in late November.”

In November last year BirdLife International called for comment on up-listing the Shy Albatross Thalassarche cauta from Near Threatened to Vulnerable and the Amsterdam Albatross D. amsterdamensis being down-listed from Critically Endangered to Endangered.  These two calls remain open for comment.

Click here for information on how to submit comments on any of the five ACAP-listed species.

With thanks to Ross Wanless.

John Cooper, ACAP Information Officer, 09 June 2017

Penguin Island forms part of the South Shetland Islands lying off the Antarctic Peninsula. It lies close to the southern coast of King George Island in front of the side of King George Bay. It is an oval-shaped ice-free island 1.4 km wide and 1.7 km long. The island is an old volcano no longer active. Its cone is the 170-m high Deacon Peak, which slopes gently down to a landing beach.

Penguin Island seen from Turret Point on King George Island

A Chinstrap Penguin colony on Penguin Island

The Southern Giant Petrel Macronectes giganteus is the only ACAP-listed species breeding on Penguin Island. Breeding grounds are located on sloping terrain made up of lichens, mosses, vascular plants and scree among irregular formations of volcanic origin above low cliffs close to the sea. Most nests in small groups or singly are located in the north-east of the island, facing Turret Point (ALSA Breeding Site No. 89) on King George Island.

A Southern Giant Petrel colony on Penguin Island

A white-phase Southern Giant Petrel breeding on Penguin Island

A Southern Giant Petrel on its pebble nest on Penguin Island

A Southern Giant Petrel's nest of lava pebbles, shells and lichen on Penguin Island

 Population censuses of Southern Giant Petrels made by Brazilian researchers from the Universidade do Vale do Rio dos Sinos show inter-annual variation in breeding pair numbers, with only 138 pairs in 2011/12 (on 10 December) (another count is of 288 pairs recorded in 2012) and 418 pairs in the 2012/13 season (on 10 December).  Earlier censuses by the Antarctic Site Inventory from 1997/98 to 1999/2000 ranged from 439 to 634 occupied nests, suggesting a population decrease since then.

Tourist visits to the island are managed by a Visitor Site Guide document produced by the Antarctic Treaty System, which provides specific procedures for visitors to follow; three giant petrel breeding sites are closed to visitors with a 50-m precautionary distance.  Penguin Island was previously classified as an Important Bird Area by BirdLife International, but due to the decline in its Southern Giant Petrel population it no longer qualifies as one and so has been delisted.

Photographs by Maria Virginia Petry.

With thanks to Patricia Pereira Serafini .

Selected Literature:

Antarctic Treaty System 2014.  Penguin Island Antarctic Treaty Visitor Site Guide.  2 pp.

Harris, C.M., Lorenz, K., Fishpool, L.D.C., Lascelles, B., Cooper, J., Coria, N.R., Croxall, J.P., Emmerson, L.M., Fijn, R., Fraser, W.L., Jouventin, P., LaRue, M.A., Le Maho, Y., Lynch, H.J., Naveen, R., Patterson-Fraser, D.L., Peter, H.-U., Poncet, S., Phillips, R.A., Southwell, C.J., van Franeker, J.A., Weimerskirch, H., Wienecke, B. & Woehler, E.J. 2015. Important Bird Areas in Antarctica 2015.  Cambridge: BirdLife International and Environmental Research & Assessment Ltd.  302 pp.

Jablonski, B. 1984. Distribution and numbers of penguins in the region of King George Island (South Shetlands Islands) in the breeding season 1980/1981. Polish Polar Research 5: 17-30.

Naveen, R. 1997.  The Oceanites Site Guide to the Antarctic Peninsula.  Chevy Chase: Oceanites Inc.  129 pp.

Naveen, R. 2003. Compendium of Antarctic Peninsula Visitor Sites 2nd Edition.  A Report to the United States Environmental Protection Agency. Chevy Chase: Oceanites Inc.  381 pp.

Naveen, R., Forrest, S.C., Dagit, R.G., Blight, L.K., Trivelpiece, W.Z. & Trivelpiece, S.G. 2000.  Censuses of penguin, Blue-eyed Shag, and Southern Giant Petrel populations in the Antarctic Peninsula region, 1994-2000.  Polar Record 36: 323-334.

Patterson, D.L., Woehler, E.J., Croxall, J.P., Cooper, J., Poncet, S., Peter, H.-U., Hunter, S. & Fraser, M.W. 2008. Breeding distribution and population status of the Northern Giant Petrel Macronectes halli and Southern Giant Petrel M. giganteus. Marine Ornithology 36: 115-124 & appendices.

Poncet, S. & Poncet, J. 2007.  Southern Ocean Cruising Second Edition.  Cambridge: Environmental Research & Assessment.  160 pp.

Maria Virginia Petry & Júlia Victória Grohmann Finger, Laboratório de Ornitologia e Animais Marinhos, Universidade do Vale do Rio dos Sinos, São Leopoldo, Brazil, 08 June 2017

Elephant Island is part of the South Shetlands Island group in Maritime Antarctica and is located in the outer reaches of the archipelago, approximately 245 km north-east of the Antarctic Peninsula.  Stinker Point is located on the south-western coast of Elephant Island. The area consists of 4.3 km of coastline, comprising 13 narrow sandy beaches divided by steep rocky walls.  Plateau areas with large fields of the moss Sanionia uncinata and scree-covered areas also occur.

View of one of Stinker Point's beaches from the South Plateau

View from the North Plateau and a small breeding group of Southern Giant Petrels

A Southern Giant Petrel colony at Stinker Point. Across the water are Gibbs and Clarence Islands, photograph by Uwe Horst Schulz 

Throughout the austral summer Stinker Point’s plateaus and beaches remain ice-free, allowing many seabirds and marine mammals to utilize the area for breeding.  The area has been monitored since 1985 by Brazilian researchers from the Universidade do Vale do Rio dos Sinos.

The Southern Giant Petrel or “stinker” Macronectes giganteus is the only ACAP-listed species that breeds at Stinker Point, named after the species.  Two major colonies (North Plateau and South Plateau) and some single nests comprise the population of Southern Giant Petrels over a total area of 5.0 ha.  Both colonies are located on plateaus up to 75 m high from where the birds can easily take off. The breeding ground is irregular with gentle slopes surrounded by a mixed field of mosses, lichens, grasses and scree sediments. Most nests are constructed from pebbles and moss.

Southern Giant Petrels breeding at Stinker Point

Ground censuses made in the austral summers from 2009/10 to 2012/13 indicate an average population of 903 breeding pairs. The last count (November 2012) was of 930 breeding pairs. Even though the numbers from 2009 and 2012 are similar, the population showed inter-annual variation among the sampled years.

A comparison with earlier censuses made during the mid-1980s and early 1990s shows that the population has increased since then (in 1971 the population was assessed as 295 pairs).

BirdLife International has designated Stinker Point as an Important Bird Area (ANT033), notably for its Chinstrap Penguin Pygoscelis antarctica population.

Photographs by Maria Virginia Petry & Uwe Horst Schulz.

With thanks to Patricia Pereira Serafini.

Selected Literature:

Colabuono, F.I., Vander Pol, S.S., Huncik, K.M., Satie, T., Petry, M.V., Kucklick, J.R. & Montone, R.C. 2016. Persistent organic pollutants in blood samples of Southern Giant Petrels (Macronectes giganteus) from the South Shetland Islands, Antarctica. Environmental Pollution 216: 38-45.

Harris, C.M., Lorenz, K., Fishpool, L.D.C., Lascelles, B., Cooper, J., Coria, N.R., Croxall, J.P., Emmerson, L.M., Fijn, R., Fraser, W.L., Jouventin, P., LaRue, M.A., Le Maho, Y., Lynch, H.J., Naveen, R., Patterson-Fraser, D.L., Peter, H.-U., Poncet, S., Phillips, R.A., Southwell, C.J., van Franeker, J.A., Weimerskirch, H., Wienecke, B. & Woehler, E.J. 2015. Important Bird Areas in Antarctica 2015.  Cambridge: BirdLife International and Environmental Research & Assessment Ltd.  302 pp.

Patterson, D.L., Woehler, E.J., Croxall, J.P., Cooper, J., Poncet, S., Peter, H.-U., Hunter, S. & Fraser, M.W. 2008. Breeding distribution and population status of the Northern Giant Petrel Macronectes halli and Southern Giant Petrel M. giganteus.  Marine Ornithology 36: 115-124 & appendix.

Petry, M.V. 1994. Aves reprodutoras em Stinker Point, Arquipélago das South Shetlands. MSc Thesis, Pontifícia Universidade Católica do Grande do Sul, Porto Alegre.  275 pp.

Schulz, U.H., Krüger, L. & Petry, M.V. 2014. Southern Giant Petrel nest attendance patterns under extreme weather conditions. Zoological Science 31: 501-506.

Maria Virginia Petry & Júlia Victória Grohmann Finger, Laboratório de Ornitologia e Animais Marinhos, Universidade do Vale do Rio dos Sinos, São Leopoldo, Brazil, 07 June 2017