White-chinned Petrel, watercolour for ACAP by Anju Rajesh of Artists & Biologists Unite for Nature (ABUN)

Cristiane Kolesnikovas (Associação R3 Animal, Vermelho, Florianópolis-Santa Catarina, Brazil) and colleagues have published in the open-access journal Marine Ornithology on two mass strandings of globally Vulnerable White-chinned Petrels Procellaria aequinoctialis in Brazil.

The paper’s abstract follows:

“Bycatch is a significant threat for albatrosses and petrels in general but especially within Brazilian waters. As part of a monitoring program, Projeto de Monitoramento de Praias da Bacia de Santos (PMP-BS), an unusually high number of White-chinned Petrels Procellaria aequinoctialis was recorded at Santa Catarina Island: 72 birds from August 2015 to July 2016 (60 dead and 12 alive) and 31 birds from 29 December 2015 to 05 January 2016 (28 dead and 3 alive). Evaluation of the carcasses showed that 12 birds had external evidence of anthropogenic interaction, and necropsy demonstrated that at least two had perforation of internal organs due to hook attachment. Hooks were identified as the type used by the Itaipava fleet. This fleet targets dolphinfish Coryphaena hippurus; tunas Thunnus obesus, T. alalonga, and T. albacares; and swordfish Xiphias gladius, and it typically operates in waters off southeastern Brazil. Although Brazil has strict laws to prevent albatross and petrel bycatch, enforcing bycatch mitigation measures has been a challenge. It is crucial to understand the dynamics of threats and their effects on populations, especially in terms of mass mortalities. For now, beach surveys can at least document the incidence of this problem.”

Reference:

Kolesnikovas, C.K.M., Ferreira, E.C., Assumpção, C.C.A. & Serafini, P.P. 2021.  Unusual mass stranding event of White-chinned Petrels Procellaria aequinoctialis in Santa Catarina State, southern Brazil.  Marine Ornithology 49: 183-187.

John Cooper, ACAP Information Officer, 27 October 2021, corrected 18 December 2021

 
Left and centre: Scopoli's, right Cory's; from the publication

Robert Flood (FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch, South Africa) and Ricard Gutiérrez have published in the open-access journal Marine Ornithology on separating Scopoli's Calonectris borealis and Cory's C. diomedea Shearwaters from ther underwings.

The paper’s abstract follows:

“The genus Calonectris contains four species: Streaked Shearwater C. leucomelas (which breeds in the North Pacific mainly on islands off Korea, Japan, and Taiwan), Scopoli's Shearwater C. diomedea (which breeds mainly in the Mediterranean Sea), Cory's Shearwater C. borealis (which breeds mainly on islands in the Northeast Atlantic Ocean), and Cape Verde Shearwater C. edwardsii (which is an endemic breeder of the Cape Verde Islands).  In this study, we were concerned with the field separation of the cryptic pair Scopoli's Shearwater and Cory's Shearwater, only briefly considering the more easily recognised Streaked Shearwater and Cape Verde Shearwater.  Background information is summarised in Appendix 1, available on the website).”

Reference:

Flood, R.L. & Gutiérrez, R. 2021.  Field separation of Cory's Calonectris borealis and Scopoli's C. diomedea Shearwaters by underwing pattern. Marine Ornithology 49: 311-320.

John Cooper, ACAP Information Officer, 26 October 2021

Antipodean Albatross, artwork by Kitty Harvill of ABUN for ACAP, from a photograph by Kirk Zufelt

Samhita Bose and Igor Debski (Department of Conservation, Wellington, New Zealand) have reported to the department’s Conservation Service Programme on the second year of satellite tracking Nationally Critical and globally Endangered Antipodean Albatrosses Diomedea antipodensis from Antipodes Island to ascertain overlap with fisheries.

The report’s abstract follows:

“Bycatch in fisheries has been identified as the greatest known threat to the endangered Antipodean albatross (Diomedea antipodensis antipodensis), which is declining at 5% per year. Tracking birds to quantify overlap with fishing activity posing bycatch risk and identifying relevant fleets is a key conservation management task for the recovery of this population. We report on the second year of intensive satellite tracking, with 40 tags deployed on adult females and males during 2020, supplementing 63 tracked birds in 2019 (consisting of adult males, adult females, and juveniles). For each bird location obtained, we estimated the daily overlap with fishing effort, using individual vessel data derived by Global Fishing Watch from vessel monitoring systems. We made refinements to methods used to report on the 2019 tracking, including the use of updated fishing effort data sets and improved bird location filtering. Tag longevity was more consistent in 2020, providing information over the entire austral winter when most overlap with fishing activity occurs. These methods allowed us to quantify the overlap by geographic or jurisdictional area, year, season, and fishing fleet.

Over both years, overlap with fishing activity was highest for pelagic longline fishing effort, primarily in the high seas of the Western Pacific, particularly in the mid-Tasman Sea and north-east of New Zealand. Adult females had higher overlap with pelagic longline fishing effort compared to males, which corresponded to recent research showing a higher relative reduction in female survival as an important driver of the Antipodean albatross population decline. Overlap by flag-state fleet showed that the same key fleets overlapped Antipodean albatross in both years. Some individual vessels overlapped with as many as one third of tracked Antipodean albatross in either year. In 2020, foraging ranges of birds extended further north than in 2019, with birds travelling up to 21°S, where there are no mandatory requirements for seabird bycatch mitigation use by relevant Regional Fisheries Management Organisations. Individual birds may overlap with as many as 88 different pelagic longline fishing vessels per year, increasing their potential exposure to bycatch risk. A range of effective and proven seabird bycatch mitigation options are readily available, and we identified the ports used by vessels that overlapped with tracked birds to facilitate bycatch reduction outreach efforts to these vessels.

Further tracking of Antipodean albatross in 2021 and beyond will provide for an expanded dataset to further improve our understanding of interannual variation and provide greater certainty on the range of fisheries that may pose potential bycatch risk to this endangered seabird.”

Access the previous report for 2019 from here.

See the newly released ACAP/DOC infographic for the beleaguered Antipodean Albatross and click here to view a graphic depiction of the interactions of tracked juvenile Antipodean Albatross White 44J from Antipodes Island with the Taiwanese longliner Kuan Huang Fa that ultimately led to her demise.

Reference:

Bose, S. & Debski, I. 2021.  Antipodean albatross spatial distribution and fisheries overlap 2020.  Wellington: Department of Conservation.  36 pp.  A set of supplementary data tables containing input data and detailed overlap results are available on request.

John Cooper, ACAP Information Officer, 25 October 2021

 
A Spectacled Petrel calls from outside its burrow on Inaccessible Island

NOTE:  This post continues an occasional series that features photographs of the 31 ACAP-listed species, along with information from and about their photographers.  Here, Peter Ryan, Director of the University of Cape Town’s FitzPatrick Institute of African Ornithology, writes about the population research he has conducted over a span of three decades on the Vulnerable Spectacled Petrel Procellaria conspicillata, endemic to the South Atlantic’s Inaccessible Island.  Professor Ryan’s account completes photo essays for the five members of the genus, all of which are ACAP listed.  Access accounts for all the species covered so far in the series in the Photo Essays section on this website.

Peter Ryan weighs a Vulnerable Inaccessible Finch Nesospiza acunhae on Inaccessible Island in 2018; photograph by Ben Dilley

I am often asked what is my favourite bird.  I don’t have an answer; there are so many cool birds that it’s impossible to pick just one.  One contender for the title is the Spectacled Petrel, although in truth, this is coloured as much by my fondness for Inaccessible Island, its sole breeding site, as it is for the bird itself.

A Spectacled Petrel at sea, known as a ‘Ringeye’ to Tristan Islanders

I have been extremely privileged to visit many seabird breeding islands, but the island where I have spent most time is Inaccessible, the larger of the two uninhabited islands in the Tristan archipelago. I first visited Inaccessible for a few hours in 1984, and at the time didn’t think that I would ever get back there.  I was landed by helicopter at Blenden Hall, near the west point of the island, far from where Spectacled Petrels breed on the island plateau.  It was only in 1987, when I returned for a few weeks to study the metabolic rate of the endemic and Vulnerable Inaccessible Island Rail Laterallus rogersi, the world’s smallest surviving flightless bird, that I finally got to see a Spectacled Petrel at its nest burrow.

Out in the daytime: a Spectacled Petrel at its burrow entrance

I returned to Inaccessible the following two years, culminating in a summer-long stay while conducting the research for my PhD on the ecology and evolution of Tristan’s Nesospiza finches, or buntings as they were known then.  However, with assistance from Coleen Moloney, I also made observations on Spectacled Petrels, including recording their calls, and testing their response to playback of White-chinned Petrel P. aequinoctialis calls.  This culminated in a paper splitting the two species, a decision that was later supported with genetic evidence by Mareile Techow.  This is the only time that I have seen Spectacled Petrel chicks – large bundles of down already bearing the distinctive white spectacle that they bear throughout their lives.

Flying in unison: a White-chinned (left) and a Spectacled Petrel

I managed to spend another summer on Inaccessible in 1999/2000.  My main goal was to assess whether there had been any change in the distribution and abundance of hybrid finches on the island plateau in the decade since my PhD study.  But to help fund the visit, I obtained a grant to reassess the population size of Spectacled Petrels.  This was when concern about the impact of long-line bycatch on albatrosses and large petrels was at its peak, and there was real concern about the status of the petrel, given its modest population size and known mortality on long-lines off Brazil.  At that time, the most recent population assessment was Mike Fraser’s estimate of 1000 pairs, made during the Denstone Expedition to Inaccessible in 1982.  To our surprise, we found that there were at least 4000 occupied burrows on the island.  Either Mike’s estimate was very conservative, or the species was doing well despite the impacts of long-line bycatch.

With no introduced cats or rodents, Spectacled Petrels can breed undisturbed

I returned in 2004 with Cliff Dorse to repeat the Spectacled Petrel survey.  We estimated a population of some 10 000 pairs, and further surveys in 2009 (with Rob Ronconi) and in 2018 (with Ben Dilley) confirmed that the population was increasing in leaps and bounds, with the most recent estimate as high as 30 000 pairs.  It appears that the Spectacled Petrel narrowly avoided extinction at the end of the 19th Century, when feral pigs roamed Inaccessible Island.  Fortunately, the pigs died out before they ate the last of the petrels, and the Spectacled Petrel population has been recovering ever since.  As a consequence, the species’ threatened status was moved from Critically Endangered to Vulnerable in 2007.  It is likely that a sister population used to breed at Amsterdam and perhaps also on St Paul, French islands in the central Indian Ocean, but were extirpated by the menagerie of mammals introduced to those islands.

A Spectacled Petrel glides over Bog Ferns Blechnum palmiforme on Inaccessible Island at dusk
Photographs by Peter Ryan

Inaccessible Island is now formally protected as a Nature Reserve, and forms part of the Gough and Inaccessible Islands World Heritage Site.  I applaud the foresight of the Tristan community for conserving these magnificent islands and their globally important biota.

Selected Publications:

Fraser, M.W., P.G. Ryan & B.P. Watkins 1988.  The seabirds of Inaccessible Island, South Atlantic Ocean.  Marine Ornithology  16: 7-33.

Reid, T.A., Ronconi, R.A., Cuthbert, R.J. & Ryan, P.G. 2014.  The summer foraging ranges of adult Spectacled Petrels Procellaria conspicillata.  Antarctic Science 26: 23-32.  [click here].

Ryan, P.G. 1998.  The taxonomic and conservation status of the Spectacled Petrel Procellaria conspicillata.  Bird Conservation International  8: 223-235.

Ryan, P.G. & Moloney, C.L. 2000.  The status of Spectacled Petrels Procellaria conspicillata and other seabirds at Inaccessible Island.  Marine Ornithology  28: 93-100.

Ryan, P.G. & Ronconi, R. 2011.  Continued increase in numbers of spectacled petrels Procellaria conspicillata.  Antarctic Science 23: 332-336.  [click here].

Ryan, P.G., Dilley, B.J. & Ronconi, R.A. 2019.  Population trends of Spectacled Petrels Procellaria conspicillata and other seabirds at Inaccessible Island.  Marine Ornithology 47: 257-265.  [click here].

Ryan, P.G., Dorse, C. & Hilton, G.M. 2006.  The conservation status of the Spectacled Petrel Procellaria conspicillata.  Biological Conservation 131: 575-583.

Techow, N.M.S.M., Ryan, P.G. & O'Ryan, C. 2009.  Phylogeography and taxonomy of White-chinned and Spectacled Petrels.  Molecular Phylogenetics and Evolution  52: 25-33.  [click here].

Peter Ryan, FitzPatrick Institute of African Ornithology, University of Cape Town, 22 October 2021