The globally Endangered Atlantic Yellow-nosed Abatross Thalassarche chlororhynchos breeds only on the Tristan-Gough islands in the South Atlantic, part of the UK’s Overseas Territory of St Helena, Ascension and Tristan da Cunha.  A helicopter-borne aerial photographic survey of the main island of Tristan da Cunha conducted in 2015 has resulted in a breeding estimate of 15 000 pairs (with a range of 9300 to 24 000 pairs), according to a recent report by the UK’s Royal Society for the Preservation of Birds (RSPB).

The aerial survey, the first conducted for the island, is in accord with ACAP’s survey priorities for the species.  A previous estimate for the main island, of 16 000 to 30 000 breeding pairs by Mike Richardson, was based on ground observations made from visits to “all quarters of the island on numerous occasions between 1972 and 1974”.  He provided estimates for four separate quarters of the island, with larger numbers found farther away from the island’s settlement in the north-west quadrant.

Prior to the 1970s the only published estimate is of 3000 pairs over 1950-52 by Sir Hugh Elliott.  Richardson ascribed the increase over two decades to “cessation of egg collecting” on the main island by the Tristan Islanders.  The Atlantic Yellow-nosed Albatross is now fully protected throughout the island group.

The following text describing the 2015 survey is taken from the RSPB’s Annual Report for 2016.

“One of the smallest albatross species in the world, the endangered Atlantic yellownosed albatross, only breeds on the islands of Tristan da Cunha in the South Atlantic. Tracking studies show that they forage right across the South Atlantic Ocean, where sadly they are sometimes accidentally caught as bycatch in fisheries. The Albatross Task Force, which the RSPB leads on behalf of BirdLife International, is working with fishermen [sic] to reduce albatross bycatch in this area. Monitoring the success of these efforts requires robust population estimates of the breeding colonies. Historically, the main island of Tristan da Cunha has been the species’ stronghold but the only estimate of its population (16,000- 30,000 breeding pairs) dates from 1974, and was based on general impressions only. In partnership with the Tristan da Cunha Conservation Department and the Percy FitzPatrick Institute of African Ornithology, the RSPB conducted a survey by helicopter in September 2015. By merging more than 600 photographic images, and examining areas of suitable habitat, we estimate that the current population of Tristan da Cunha is around 15,000 pairs (9,300–24,000 pairs). This estimate is being complemented by an updated population estimate from Gough Island, where the previous estimate of 5,100 pairs dates from 2001. Robust population estimates help us to understand the population trend of this globally- threatened species, enabling us to monitor the effectiveness of our actions to reduce bycatch of these beautiful birds at sea.”

Atlantic Yellow-nosed Albatross chick, photograph by Andrea Angel and Ross Wanless

Selected Literature:

Cuthbert, R.J., Ryan, P.G., Cooper, J. & Hilton, G. 2003.  Demography and population trends of the Atlantic Yellow-nosed Albatross Thalassarche chlororhynchos.  Condor 105: 439-452.

Elliott, H.F.I. 1957.  A contribution to the ornithology of the Tristan da Cunha group.  Ibis 99: 545-586.

Hayhow, D.B., Bond, A.L., Douse, A., Eaton, M.A., Frost, T., Grice, P.V., Hall, C., Harris, S.J., Havery, S., Hearn, R.D., Noble, D.G., Oppel, S., Williams, J., Win, I. & Wotton, S. 2017.  The State of the UK’s Birds 2016.  Sandy: Royal Society for the Preservation of Birds.  46 pp.

Richardson, M.E. 1984.  Aspects of the ornithology of the Tristan da Cunha group and Gough Island, 1972-1974. Marine Ornithology 12: 123-201.

[Tristan da Cunha] 2006.  The Conservation of Native Organisms and Natural Habitats (Tristan da Cunha) Ordinance 2006.  The St. Helena Gazette Extraordinary Vol. XLIV, No. 13.

John Cooper, ACAP Information Officer, 13 April 2017

Southern Africa, generally well covered by books on particular groups of birds, now has a seabird book to fill a notable gap and join the existing books on game birds, water birds and raptors.  Guide to Seabirds of Southern Africa by Peter Ryan, published by Struik Nature last month, covers 132 seabird species, including vagrants but also 12 breeding endemics, which occur in southern Africa (primarily Namibia and South Africa) and in the Southern Ocean and its oceanic islands south of Africa.

This book is primarily an identification guide, with each species illustrated with colour photos and a thumb-nail distribution map.  As well as a description and advice on how to identify them, the species’ texts cover status and biology.  Species have anything from two to 11 (mainly three to five) photos showing birds in flight and at rest; photos, mostly by the author, are quite small, but nearly all of them are sharp and well exposed.  For some species (e.g. Wandering Albatross Diomedea exulans and Kelp Gull Larus dominicanus) plumage changes with age are illustrated. These accounts are supported by up to two pages describing each taxonomic group (mainly families).  A detailed introduction covers such subjects as the Ocean environment, Making a living, Seabirds on the move, Raising a family, Seabird conservation, Watching seabirds and How to use this book.

Procellariiform tubenoses form the bulk of the book.  Of the 31 species listed by the Agreement on the Conservation of Albatrosses and Petrels (ACAP), Peter Ryan’s guide includes 17 albatross taxa (unlike ACAP’s treatment, the White-capped Thalassarche steadi is regarded as a subspecies of the Shy T. cauta), five species of petrels and the Northern Hemisphere’s Balearic Shearwater Puffinus mauretanicus - over two thirds of the ACAP total.  And who would have guessed that as many as 10 other species of penguins have been recorded in the region in addition to the southern African endemic and globally Endangered African Penguin Spheniscus demersus (there are only 18 world-wide)?

The book is nicely up to date.  For example the recent (and unexpected) discoveries made by Peter and his colleagues of Blue Petrel Halobaena caerulea and Macgillivray’s Prion Pachyptila macgillivrayi breeding on Gough Island in the South Atlantic are each given full treatment.  The latest findings on the taxonomic status of the shearwater group is taken into account, with the genus Ardenna adopted for four species.  The confusing situation with a white-bellied morph of the Black-bellied Storm Petrel Fregetta tropica that breeds in the Tristan da Cunha group alongside the White-bellied Storm Petrel F. grallaria, worked out by the author, is also given coverage with a photo pair to compare subtle differences.

Always tricky with a seabird book: which marine-frequenting species to cover, which to leave out?  There is no firm rule on this one.  The guide includes a few marginal seabirds, for example Reed Cormorant Phalacrocorax africanus, Grey-headed Gull Larus cirrocephalus and Whiskered Tern Chlidonias hybrida, which are all pretty much shorebirds at best along most of the southern African coast.  In contrast, Black-necked Grebe Podiceps nigricollis and Great White Pelican Pelecanus onocrotalus are not included, although they do occur at sea reasonably regularly in a few sheltered inshore areas within southern Africa, notably off the Namibian coast.

Professor Peter Ryan, Director of the well-known Percy FitzPatrick Institute of African Ornithology at the University of Cape Town, was awarded A-rating scientist status by South Africa’s National Research Foundation last December. This is the highest accolade in the NRF’s rating system to rank researchers in the country and recognizes an international leader in the field.  Peter is the first A-rated ornithologist in South Africa and one of the few A-rated scientists who have worked within the South African National Antarctic Programme (SANAP) (click here).

Largely due to the Fitztitute’s impressive output of research articles in top-tier international journals under Peter’s leadership, the Centre for World University Rankings has this month placed the University of Cape Town joint third in Ornithology out of over 26 000 higher-education institutions assessed (click here).  Looking good for the Institute where I spent the larger part of my ornithological career.

Later this month, the NGO BirdLife South Africa will hold its Annual General Meeting among seabirds on a five-day cruise into the Southern Ocean on the liner MSC Sinfonia (with so far 1907 birders booked into 924 cabins!)  Peter will be aboard as one of the expert guides, and I imagine several hundred copies of his excellent and practically error-free new book will be aboard as well.

Lastly, and on a personal note, I was greatly touched to read that Peter has dedicated his seabird book to myself.  Seems my taking him, first as a schoolboy then as an undergraduate, on outings and field trips to study seabirds on southern Africa’s coasts and guano islands back in the 1980s has paid off handsomely!  He has been a valued friend and colleague ever since.

Reference:

Ryan P.[G.] 2017.  Guide to Seabirds of Southern Africa.  Cape Town: Struik Nature.  160 pp.  ISNB 978-1-77584-519-5.  Paperback, many photographic illustrations.  South African Rands 180.00.  www.penguinrandomhouse.co.za.

John Cooper, ACAP Information Officer, 12 April 2017

Samantha Patrick (School of Environmental Science, University of Liverpool, UK) and Henri Weimerskirch have published in the Journal of Animal Ecology on foraging site and habitat fidelity in Black-browed Albatrosses Thalassarche melanophris.

The paper’s summary follows:

“There is widespread evidence that within populations, specialists and generalists can coexist and this is particularly prevalent in marine ecosystems, where foraging specialisations are evident.

While individuals may limit niche overlap by consistently foraging in specific areas, site fidelity may also emerge as an artefact of habitat choice, but both drivers and fitness consequences of site fidelity are poorly understood.

Here, we examine an individual metric of site and habitat fidelity, using tracking data collected over 11 years for black-browed albatrosses (Thalassarche melanophris). Fidelity was calculated as the similarity between pairs of foraging zones, quantifying measures for within and between years. Foraging areas were identified using area-restricted search, defined as periods during which birds decrease speed and increase turning.

Our results demonstrate that birds were considerably more specialised in the habitat in which they forage than the exact location they use within years, and there was a similar pattern between years. However, despite this, it was site fidelity that explained reproductive success. Within a single year, females which were more faithful to a specific location had higher reproductive success than non-specialists, and between years there was a tendency for both sexes.

Our results suggest that black-browed albatrosses are highly faithful in their foraging habitat but it is rather site fidelity that is more clearly associated with reproductive success.”

Black-browed Albatross, photograph by Genevieve Jones

Reference:

Patrick, S.C. & Weimerskirch, H. 2017.  Reproductive success is driven by local site fidelity despite stronger specialisation by individuals for large-scale habitat preference.  Journal of Animal Ecology  doi: 10.1111/1365-2656.12636.

John Cooper, ACAP Information Officer, 11 April 2017

André Raine (Kaua‘i Endangered Seabird Recovery Project, Hanapëpë, Kaua‘i, Hawai‘i, USA) and colleagues have published in the journal Pacific Science on the petrel and shearwater populations of Moku‘ae‘ae Rock Islet off the Hawaiian island of Kauai.

The paper’s abstract follows:

“Moku‘ae‘ae Rock Islet is located off the north shore of Kaua‘i and is protected as a Hawai‘i State Seabird Sanctuary. In the late 1970s it was also the site of a cross-fostering project for the endangered Newell’s Shearwater, Puffinus newelli. Few avifauna surveys have been undertaken on the islet, and none since 2007. In 2013 and 2015, we conducted burrow searches across the entire islet to obtain breeding population estimates for each species and to evaluate whether the Newell’s Shearwater had become established as a breeding species after the cross-fostering project. Auditory surveys were also conducted for 2 hr after sunset and 1.5 hr before sunrise, which are the peak calling periods for the Newell’s Shearwater on Kaua‘i. A total of seven seabird species was recorded on the islet, of which three, Bulwer’s Petrel, Bulweria bulwerii; Wedge-tailed Shearwater, Ardenna pacifica; and Red-tailed Tropicbird, Phaethon rubricauda, were confirmed breeding. This is the first time Bulwer’s Petrel has been confirmed breeding on Moku‘ae‘ae. Searches for Newell’s Shearwater did not produce evidence that this species breeds on the islet, suggesting that the cross-fostering project was not successful. Although the islet is small, it represents an important refuge for seabird species. However, high levels of depredation were recorded on Bulwer’s Petrel; we conclude that these were all killed by the introduced Barn Owl, Tyto alba, based on disposition of the bodies and the injuries they had sustained. Management recommendations for the islet include creation of a management plan, annual breeding bird surveys, annual rat monitoring, and Barn Owl control.”

Newell's Shearwater, photograph by Eric Vanderwerf

With thanks to André Raine.

References:

Byrd, G.V., Sincock, J.L., Telfer, T.C., Moriarty, D.I. & Brady, B.G. 1984.  A cross-fostering experiment with Newell’s race of Manx shearwater. Journal of Wildlife Management 48: 163-168.

Raine, A.F., Boone, M. & Banfield, N. 2017.  An updated avifauna of Moku‘ae‘ae Rock Islet, Kaua‘i.  Pacific Science 71: 67-76.

John Cooper, ACAP Information Officer, 10 April 2017