Cape Verde Shearwater at sea

Lara Cerveiro (Marine and Environmental Sciences Centre, University of Coimbra, Portugal) and colleagues have published in the journal Marine Environmental Research on variations in foraging trips of breeding Near Threatened Cape Verde Shearwater Calonectris edwardsii.

The paper’s abstract follows:

“Pelagic seabirds exhibit plasticity in foraging characteristics in relation to oceanographic conditions.  This should be particularly relevant in tropical marine environments where food resources are naturally more unpredictable.  We studied how inter-annual variations (2013–2018) in tropical oceanographic conditions (driver of oceanic productivity) can influence the spatial and trophic ecology of Cape Verde shearwater (Calonectris edwardsii) during the breeding season.  During years of poor oceanographic conditions around the colony, birds engaged in longer trips to West Africa, showed higher spatial and behavioural consistency, and presented a wider isotopic niche.  Opposite patterns were generally found for years of good oceanographic conditions, when birds foraged more on their colony surroundings.  New foraging areas off West Africa were highlighted as relevant, especially during years of poor environmental conditions.  This study highlights the need for long-term studies to assess variation in foraging areas and foraging decisions by seabird populations.”

Reference:

Cerveira, L.R., Ramos, J.A., Rodrigues, I., Almeida, N., Araújo, P.M., dos Santos, I., Vieira, C.,  Jorge M. Pereira, J.M., Ceia, F.R., Geraldes, P., Melo, T. & Paiva, V.H. 2020.  Inter-annual changes in oceanic conditions drives spatial and trophic consistency of a tropical marine predator.  Marine Environmental Research 162.  doi.org/10.1016/j.marenvres.2020.105165.

John Cooper, ACAP Information Officer, 03 November 2020

Breeding under trees: Southern Buller's Albatrosses on North East Island, Snares Islands; from the report

David Thompson (National Institute of Water & Atmospheric Research, Wellington, New Zealand) and Paul Sagar have reported to the Conservation Service Programme of New Zealand’s Department of Conservation on research conducted on Near Threatened Southern Buller's Albatrosses Thalassarche bulleri bulleri on the sub-Antarctic Snares Islands.

The report’s executive summary follows:

“This report presents a summary of the results of counts of southern Buller’s albatrosses Thalassarche bulleri bulleri breeding at the Snares Islands|Tine Heke from 11-17 March 2020 and compares these results with those obtained using similar methods during 1969, 1992, 1997, 2002, 2014 and 2019. In addition, the results of detailed demographic studies at three study colonies are presented. The count used similar methods, and was completed at a similar time of year, to previous counts completed during 1969, 1992, 1997, 2002 and 2014. The current survey of North East Island was incomplete due to adverse weather. However, the total of 5164 breeding pairs recorded along the East Coast, North Promontory, South Coast and West Coast was very similar to the 5305 breeding pairs estimated in the same areas in 2014. This result indicates that the increase in size of the breeding population over the period 1969-2002 has not continued. An additional 621 breeding pairs were estimated on Broughton Island in 2019. Demographic studies at the three study colonies on North East Island have been undertaken annually 1992-2017, and so this report incorporates some of these data in the current analysis. Estimates of the numbers of breeding pairs, made by recording the contents of each nest mound, increased in all three colonies over the numbers recorded during 2019. With the assumption that the combined total number of breeding pairs in the three study colonies was representative of North East Island as a whole then the breeding population probably peaked in 2005-2006 and has since undergone marked annual variations. A total of 245 birds previously banded in the study colonies as breeding adults of unknown age were recaptured. A further 77 breeding birds were banded in the study colonies - these are presumed to be first-time breeders. Estimates of annual survival of birds banded as breeders continued to decline, with an estimate of 0.889 in 2017. During the period 1992-2004 all chicks that survived to near-fledging in the study colonies were banded and survival rates monitored via return to the study colonies in subsequent years. This year 125 of these birds were recaptured, with birds from cohorts banded between 1999-2004 being recaptured for the first time. This demonstrates the long-term monitoring required to obtain reliable estimates of survival of such known-age birds. Of these 162 known-age birds recaptured, 13 were found breeding for the first time, and so were recorded as being recruited to the breeding population. A bird banded as a chick on Big Solander Island in 2002 was recaptured on an empty nest. One bird banded as a chick in 1972, was recaptured at 48 years of age. Fifty Global Location Sensing (GLS) tags were attached to the metal leg bands of breeding birds in the Mollymawk Bay study colony; these will be retrieved during 2021 and 2022. A GPS device was used to record latitude and longitude coordinates at waypoints around the perimeter of each of the three study colonies, and trail cameras will be installed in 2021 at nest sites determined from this years study.”

Reference:

Thompson, D. & Sagar, P. 2020.  Population studies of southern Buller's albatrosses on the Snares Islands|Tine Heke.   Prepared for Conservation Services Programme, Department of Conservation June 2020.  [Wellington]: NIWA. 24 pp.

John Cooper, ACAP Information Officer, 02 November 2020

Antipodean Albatross at sea off North Cape, New Zealand, 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 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). We used data from 63 satellite transmitting devices deployed on Antipodean albatross in 2019 to describe the year-round distribution of these birds by cohort (in particular, adult females and juveniles). For each bird location obtained, the overlap with fishing effort, using individual vessel data derived by Global Fishing Watch from vessel monitoring systems, was estimated at a daily temporal scale. These methods allowed a quantitative assessment of overlap by geographic or jurisdictional area, season and fishing fleet. The greatest overlap was with pelagic longline fishing effort, and that overlap was primarily in the high seas areas of the Western Pacific, particularly in the mid-Tasman Sea and to the north-east of New Zealand. Juvenile birds foraged further north than adult birds, and overlapped with fishing effort north to approximately 25°S. A number of key fishing fleets were identified as having fishing effort that overlapped with Antipodean albatross, and the ports used by these vessels were also identified. Despite limitations with the tracking data set, and using fishing effort derived from vessel monitoring systems rather than data on actual hooks set, our results can be used to help focus efforts to reduce seabird bycatch in the fisheries that overlap most with Antipodean albatross. Further tracking of Antipodean albatross in 2020 and beyond will provide for an expanded dataset to further improve our understanding of the which fisheries may pose potential bycatch risk to this endangered species.”

Reference:

Bose, S. & Debski, I. 2020.  Antipodean albatross spatial distribution and fisheries overlap 2019.  [Wellington: Department of Conservation]. 23 pp.

John Cooper, ACAP Information Officer, 30 October 2020

Sabra Kauka releases a rehabilitated Newell’s Shearwater fledgling on Kauai

The Kaua’i Endangered Seabird Recovery Project (KESRP) reports that the annual E Ho‘opomaika‘i ‘ia na Manu ‘A‘o (A Cultural Release of the Native Newell’s Shearwater) event was not slowed down by the Covid-19 crisis this year.  But instead of having school children attending as is usual (click here), this  month's ceremony was filmed so that a wider audience could view it virtually.

The 2020 event was organized by KESRP and the Save Our Shearwaters (SOS) program.  Kumu [Hawaiian teacher and practitioner] Sabra Kauka of Island School led the blessing as five Critically Endangered Newell’s Shearwater Puffinus newelli fledglings that had been grounded by light attraction and rescued by SOS were successfully released out to sea on the Hawaiian island of Kauai.

Sabra Kauka, who led the blessing, said “Releasing an Aʻo to the sky and watching it fly out over the ocean with our blessings is always a deep honour. The birds have always been an important part of our ‘aina [love of the land]."  “Because of the global pandemic, we couldn’t have school children attend the release this year, which was a real shame as their enthusiasm and joy at seeing the birds up close is such an integral part of it”, said Dr André Raine of KESRP, “However, we hope that by sharing the footage of the blessing and the birds being released more people will be able to participate in this special day and learn about the challenging journey these birds take when they leave their mountain burrows for the very first time.”

Read more about this year’s ceremony here.

KESRP is a joint project between the Department of Land and Natural Resources (DNLR) Division of Forestry and Wildlife and the Pacific Co-operative Studies Unit of the University of Hawai‘i.  SOS is a DLNR project housed at the Kaua’i Humane Society and financially supported by the Kaua’i Island Utility Cooperative.

John Cooper, ACAP Information Officer, 29 October 2020