Agreement on the Conservation of Albatrosses and Petrels

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Read about recent developments and findings in procellariiform science and conservation relevant to the Agreement on the Conservation of Albatrosses and Petrels in ACAP Latest News.

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PhD thesis. The conservation ecology of burrowing petrels on Macquarie Island

Jeremy Bird Macquarie Andrea Turbett
Jeremy Bird on Macquarie, photograph by Andrea Turbott

Jeremy ‘Jez’ Bird has been awarded his PhD by the University of Queensland for a study of burrowing petrels, including the ACAP-listed and globally Near Threatened Grey Petrel Procellaria cinerea, on Australia’s Macquarie Island.

Grey Petrel Chick Macquarie Island Jeremy Bird
A Grey Petrel chick in its burrow on Macquarie Island, photograph by Jeremy Bird

The thesis abstract follows:

“Many seabird populations are of conservation significance, either because they are rare and threatened with extinction, or because they are abundant and play an integral role in island-ocean systems. Procellariiform petrels in the families Procellariidae, Hydrobatidae and Oceanitidae are especially vulnerable to the impacts of alien invasive species on islands and as a result 45 of 97 species globally are threatened with extinction, a higher proportion than comparable bird groups. In their natural state petrels are also the most abundant seabirds, consuming prey volumes commensurate with commercial fisheries, and transferring nutrients from pelagic to terrestrial and coastal ecosystems on a scale equivalent to other global geochemical fluxes. Seabird nutrient inputs ramify to influence whole-island food-webs. To prevent seabird extinctions, and to restore nutrient pathways the whole-island eradication of invasive species has been developed as an effective conservation tool. In this thesis I explore the conservation ecology of a diverse group of petrels following the World’s largest multi-species eradication to date—the staged removals of Wekas Gallirallus australis, Feral Cats Felis catus, European Rabbits Oryctolagus cuniculus, Black Rats Rattus rattus and House Mice Mus musculus from subantarctic Macquarie Island.

Petrels are particularly challenging to study, and few quantitative data on their responses to invasive species eradication are available. Petrels nest discontinuously across rugged terrain on remote islands. Their nests are in under-ground burrows, the entrances to which are often obscured under dense vegetation. Birds are not present year-round, and only return to or leave from colonies at night. Given these inherent challenges, I review in Chapter 1 what motivates people to collect and report population estimates for petrels. Because these species are cryptic and challenging to study I undertook a meta-analysis of uncertainty in published estimates to assess overall levels and drivers of uncertainty. I concluded that the primary motivation for estimating populations is to inform species status and trend assessments, but uncertainty in generated estimates is an impediment to reliable trend detection.

The findings of the review provide the rationale for testing field methods that measure two key metrics that underpin population estimates: the proportion of burrows occupied by breeding pairs (Chapter 2), and the total number of burrows on an island (Chapter 3). Chapter 2 compares traditional techniques for estimating burrow occupancy and breeding status with my novel application of camera traps positioned at burrow entrances. I found that (i) camera traps are effective at collecting season-long activity patterns, with evidence that these can be used to distinguish breeding from non-breeding burrows, and (ii) cameras provide higher resolution data on breeding success than repeat visits to inspect burrows manually and are a low impact approach.

To understand the current size and distributions of a diverse assemblage of petrels that includes common widespread species (Antarctic Prion Pachyptila desolata) and rare localised species (Blue Petrel Halobaena caerulea and Grey Petrel Procellaria cinerea) a multi-method approach to surveys and analysis is required (Chapter 3).  I found that a model-based analysis of stratified randomised whole-island survey data was most effective for estimating Antarctic Prions, less effective for scarcer White-headed Petrels Pterodroma lessonii, but did not yield useful data for Blue or Grey Petrels, which required a targeted approach.

In the final chapters I evaluate the outcomes that invasive species management has achieved for petrels to date (Chapter 4) and projected into the future (Chapter 5). The current distribution of petrels on Macquarie Island reflects the legacy of invasive species impacts and the removal of this threat. The two established species, Antarctic Prion and White-headed Petrel are confined largely to refugial habitat, while the recolonising species Blue and Grey Petrel are occupying optimal habitat on the island’s coastal slopes. While all four species occur in superficially similar habitats in terms of vegetation type, their realized niches defined by other environmental variables including slope, elevation, and aspect are starkly different. Each species is now increasing, but the two recolonising species are increasing much more rapidly than the two established ones, at rates suggesting immigration is an important mechanism facilitating initial population recovery.

The eradication of invasive predators from Macquarie Island has achieved a major short-term goal: to prevent further seabird extinctions and facilitate threatened species recovery. I present a case for downlisting three species from state or federal threatened species lists. However, suitable habitat is currently under-utilised. Using habitat suitability modelling and inter-island inference I illustrate how the current size and distribution of petrel populations is well short of plausible carrying capacities. Full recovery of populations, and restoration of the ecological and societal benefits that they bring is decades away, but no long-term targets for population recovery exist. I present a future scenario based upon plausible model-derived population estimates to highlight the potential advantages of establishing long-term targets. The thesis concludes with my own narrative vision of a future Macquarie Island when the full post-eradication recovery has occurred in coming decades.”

See also a recent publication by Jeremy Bird from his thesis.

With thanks to Jez Bird.

Reference:

Bird, J.P. 2021.  The Conservation Ecology of Burrowing Petrels on Macquarie Island.  PhD Thesis.  Brisbane, Australia: School of Biological Sciences, The University of Queensland.  216 pp.

John Cooper, ACAP Information Officer, 30 August 2021

The Seabird Restoration Database aims to improve knowledge transfer among practitioners

laysan albatross social attraction jcnwr 12 jan 2016 8155 1 1 orig
A Laysan Albatross lands next to two decoys at the
James Campbell National Wildlife Refuge, photograph from the project website

A new initiative coming out of Hawaii aims to improve knowledge transfer among practitioners of seabird restoration around the world as the project’s website explains:

“Seabirds are one of the most threatened bird groups on the planet, with approximately 30% at risk of extinction and with 84% of all species at risk from at least one threat, primarily from invasive alien species, bycatch, poaching, and/or climate change.  Active seabird restoration tools are used to recover seabird colonies, particularly where removal of threats is not enough for long-term species conservation, yet it is unknown which restoration methods are most likely linked to conservation success.  The Seabird Restoration Database seeks to improve knowledge transfer of active restoration techniques among practitioners and enhance seabird conservation by documenting the methods and outcomes from social attraction and translocation activities applied to restore and recover seabird populations around the world.  Between 2020-2021 we will collate data from the literature, reports, databases and expert consultations to determine the species, locations, methods, and outcomes for active seabird restoration efforts.  Once completed, the database will be made publicly available.”

The Seabird Restoration Database is being managed by Pacific Rim Conservation which is based in Oahu, Hawaii.

John Cooper, ACAP Information Officer, 27 August 2021

Using trail cameras to study breeding Grey Petrels on Macquarie Island

  Kitty Harvill Grey Petrel chick acrylic 18x24 Ben Dilley
A Grey Petrel chick in its burrow, artwork in acrylics by Kitty Harvill for ACAP; after a photograph by Ben Dilley 

Jeremy Bird (School of Biological Sciences, University of Queensland, Brisbane, Australia) and colleagues have published open access in the journal Remote Sensing in Ecology and Conservation on studying ACAP-listed and Near Threatened Grey Petrels Procellaria cinerea and Blue Petrels Halobaena caerulea on Australia’s sub-Antarctic Macquarie Island using camera traps.

Jeremy Bird paper
Camera trap set-up and results: (A) checking Spypoint cameras in a Blue Petrel colony, (B) a Blue Petrel emerging from its burrow, (C) a Recconyx camera outside a Grey Petrel burrow and (D) a Grey Petrel chick close to fledging exercising outside its burrow.  From the publication

The paper’s abstract follows:

“Burrowing seabirds are important in ecological and conservation terms. Many populations are in flux due to both negative and positive anthropogenic impacts, but their ecology makes measuring changes difficult. Reliably recording key metrics, the proportion of burrows with breeding pairs and the success of breeding attempts requires burrow-level information on occupancy. We investigated the use of camera traps positioned at burrow entrances for determining the number of breeding pairs in a sample to inform population estimates, and for recording breeding success. The performance of two cameras makes we tested differed markedly, with Spypoint Force 10 trail cameras prone to malfunction while Reconyx HC600 Hyperfire cameras performed well. Nevertheless, both makes yielded season-long activity patterns for individual burrows, eliminating uncertainty around successful fledging attempts. Dimensionality reduction of activity metrics derived from camera time series suggests breeding and non-breeding burrows may be identifiable using linear discriminant analyses but sample sizes from our trial were low and group means were only significantly different during certain breeding stages (permutational multivariate analysis of variance: early chick-rearing f = 3.64, P = 0.06; late chick-rearing f = 8.28, P = 0.009). Compared with traditional techniques for determining burrow occupancy (e.g. manual burrow inspection and playback of conspecific calls at burrow entrances), camera traps can reduce uncertainty in estimated breeding success and potentially breeding status of burrows. Significant up-front investment is required in terms of equipment and human resources but for long-term studies, camera traps may deliver advantages, particularly when unanticipated novel observations and the potential for calibrating traditional methods with cameras are factored in.”

Reference:

Bird, J.P., Fuller, R.A., Pascoe, P.P. & Shaw, J.D.S. 2021.  Trialling camera traps to determine occupancy and breeding in burrowing seabirds.  Remote Sensing in Ecology and Conservation doi.org/10.1002/rse2.235.

John Cooper, ACAP Information Officer, 26 August 2021

Genetic study suggests asynchronous breeding keeps Northern and Southern Buller’s Albatrosses apart

Bullers Albatross Paul Sagar Shary Page Weckwerth

Buller's Albatross, artwork by Shary Page Weckwerth for ACAP; from a photograph by Paul Sagar

Jana Wold (School of Biological Sciences, Victoria University of Wellington, New Zealand) and colleagues report in the journal Emu - Austral Ornithology on genetic differences between Northern Thalassarche bulleri platei and Southern T. b. bulleri Buller’s Albatrosses.

The paper’s abstract follows:

“The Buller’s albatross species complex is composed of two asynchronously breeding subspecies, the Northern Buller’s albatross (Thalassarche bulleri platei) and Southern Buller’s albatross (Thalassarche bulleri bulleri). The aim of this study was to test for genetic differentiation between Northern and Southern Buller’s albatross and to reassess genetic connectivity between these populations. Genotyping-by-Sequencing (GBS) was used to estimate gene flow and genome-wide divergence using 13 T. b. platei and 40 T. b. bulleri samples. The STACKS de novo and reference guided pipelines were used to call single nucleotide polymorphisms (SNPs) for three data sets: one each for Northern and Southern Buller’s and a third for both taxa together. The number of SNPs in each de novo data set was relatively consistent from 12,148 to 11,898 for Northern and Southern Buller’s albatross collections, respectively. A random subsample of 1000 SNPs from each of the two groups indicated that mean per-site nucleotide diversity and heterozygosity were slightly higher for Northern Buller’s albatross (π = 0.335; HE = 0.322) than for either of the two Southern Buller’s albatross breeding colonies (π = 0.286 and 0.294; HE = 0.275 and 0.288). Both STRUCTURE and discriminant analysis of principal components (DAPC) consistently showed differentiated clusters corresponding to Northern and Southern Buller’s but did not resolve population structure among Southern Buller’s breeding populations. These results indicate that an asynchronous breeding season likely limits gene flow between Northern and Southern Buller’s albatross and have important implications for the taxonomic status of Buller’s albatrosses.”

Reference:

Wold, J.R., Robertson, C.J.R., Chambers, G.K., Van Stijn, T. & Ritchie, P.A. 2021.  Genetic connectivity in allopatric seabirds: lack of inferred gene flow between Northern and Southern Buller’s albatross populations (Thalassarche bulleri ssp.).  Emu - Austral Ornithology 121: 113-123.

John Cooper, ACAP Information Officer, 25 August 2021

ACAP’s Population and Conservation Status Working Group starts its virtual Sixth Meeting today

Shary Page Weckwerth Norfthern Giant Petrel 7 x 10 watercolour Laurie Smaglick Johnson

A Northern Giant Petrel  broods its chick, watercolour by Shary Page Weckwerth for ACAP; after a photograph by Laurie Smaglick Johnson

 As for nearly all international meetings affected by COVID-19, the Twelfth Meeting of ACAP’s Advisory Committee (AC12) and of two of its working groups are being held virtually; a first for ACAP.  This year’s meetings - delayed from last year by the pandemic - are now being held from 16/17 August to 1/2 September (depending on where you are in the world).  Meetings of the Seabird Bycatch Working Group and the Population and Conservation Status Working Group are preceding AC12; SBWG10 (which has already met) from 16/17 to 18/19 August, and PaCSWG6 from 23/24 to 24/25 August.  AC12 will meet from 30/31 August to 1/2 September.

PaCSWG6 is being chaired by its Co-convenors, Marco Favero from Argentina and Patricia Serafini from Brazil, with the support of Vice- Convenor Richard Phillips (UK).  The working group’s full membership and Terms  of Reference may be viewed by scrolling down from here.  Four Documents (including a Draft Meeting Agenda, PaCSWG 6 Doc 01 Rev. 1) and 22 Information Papers have been tabled for consideration, leading to an expected busy meeting over the two days allotted.  All these documents can be downloaded from this website but note that some are password protected and so only their abstracts are available to be read.

Further information is available in AC12 Circular 5 in the three official ACAP languages of English, French and Spanish on timing at different localities and lengths of the three meetings.  Congress Rental has been chosen to manage the technical aspects of the meeting, using the Interprefy platform.  Interprefy enables “relay interpretation” (involving multiple languages – three in the case of ACAP).  Congress Rental is providing technical advice to Chairs, Convenors, Secretariat, interpreters and to other participants.

John Cooper, ACAP Information Officer, 24 August 2021