Pink-footed Shearwater, gouache watercolour for ACAP by ABUN artist, Griselle Chock, after a photograph by Peter Hodum

Ryan Carle (Oikonos-Ecosystem Knowledge, Santiago, Chile) and colleagues have published in the online journal Marine Ornithology on a breeding survey of the Vulnerable and ACAP-listed Pink-footed Shearwater Ardenna creatopus.

The paper’s abstract follows:

“Species population estimates are a fundamental component of conservation planning, but there are deficiencies in reliable data for many seabirds. The Pink-footed Shearwater Ardenna creatopus is a seabird that breeds on three islands worldwide, with the largest population on Isla Mocha, Chile. We aimed to update the breeding population estimate of Pink-footed Shearwaters on Isla Mocha, comparing results from design- and model-based estimation methods. We counted shearwater burrows in 220 randomly generated five-meter-radius plots across pre-defined strata on Isla Mocha. We estimated total number of burrows using area-based extrapolation (design-based method), and separately using a model predicting burrow density based on habitat (model-based method). We multiplied burrow abundance estimates by burrow occupancy for final population estimates. The stratum-area-weighted burrow density estimate for the 15.8 km² study area was 0.0106 burrows·m^-2 (standard error [SE] = 0.0030). The average island-wide proportion of occupied burrows was 0.758 (standard deviation [SD] = 0.121). The design-based method estimated 168 209 burrows (95% confidence interval [CI] = 74 715-261 704, coefficient of variation [CV] = 0.28), and 127 503 breeding pairs (95% CI = 87 610-167 395). The model-based method estimated 233 436 burrows (95% CI = 151 237-332 179, CV = 0.19) and 181 859 breeding pairs (95% CI = 95 773-267 945, CV = 0.24). These population estimates are greater than previous estimates for Isla Mocha, whose means ranged from 19 440-42 095 breeding pairs. Because our study design differed from those used to generate previous estimates, our estimate should be considered a stand-alone result rather than an increase in the breeding population. Because of the low fit of the model-based result, the design-based result may be a more reliable estimate to use for species management efforts. Based on our estimate, approximately 90% of the Pink-footed Shearwater world population breeds on Isla Mocha, and with its restriction to only three breeding localities world-wide, the species remains vulnerable. The full manuscript in Spanish can be found in Appendix 1, available on the website.”

Reference:

Carle, R.D, Varela, T., Colodro, V., Clark-Wolf, T., Felis, J., Hodum, P., Astete Castillo, F.J. & López, V. 2024.  Breeding population size of the Pink-footed Shearwater Ardenna creatopus on Isla Mocha, Chile.  Marine Ornithology 52: 85-96.

22 May 2024

A Galápagos Petrel on its burrow nest, photograph from the Galápagos National Park Directorate

The Galápagos Petrel Pterodroma phaeopygia, endemic to Ecuador’s Galapagos Islands, is Critically Endangered.  The species has been listed by the Convention on the Conservation of Migratory Species of Wild Animals (CMS) in Annex 1 since 1979 and has been proposed in the past for listing by the Agreement on the Conservation of Albatrosses and Petrels (ACAP).  In 2019 the First International Meeting for the Conservation of the Galápagos Petrel (Primera Reunión Internacional para la Conservación del Petrel de Galápagos) was held in Puerto Ayora, Santa Cruz Island, Galapagos.  The purpose of the meeting, which ACAP attended, was to bring together researchers, governmental agencies and non-profit groups with the shared interest of coordinating future conservation actions for Ecuador’s endemic petrel and to draft an action plan (click here).

Galápagos Petrel in flight, photograph by Eric VanderWerf

The Galápagos Petrel is known to breed on five islands: Floreana, Isabela, San Cristóbal, Santa Cruz and Santiago.  Threats to the species include non-native species, both flora and fauna, and encroachment of human activities.  To address these threats the environmental NGO Galápagos Conservancy has partnered with the Galápagos National Park Directorate to implement conservation projects on three of the breeding islands: Isabela, Santa Cruz and Santiago (click here for a summary of the plans for each island).  ACAP Latest News has previously reported on the recent effort to eradicate feral cats and rodents on Floreana.

A downy Galápagos Petrel in its burrow, photograph from the Galápagos National Park Directorate

The Galápagos Conservancy writes: “With community support and international collaboration, we can ensure a future where these majestic birds continue to soar through the night skies of the Galápagos.  Management measures and decisions based on technical criteria, thanks to studies conducted, will also be critical to the conservation of this species.  The complex process of protecting this species demands constant effort, and we appreciate the support of our many donors, whose generosity supports the conservation actions implemented by our organization.  Every action, no matter how small, counts in this fight for the survival of the Galápagos Petrel.”

ACAP held a one-day workshop on gadfly petrels of the genera Pterodroma and Pseudobulweria and other small petrels in Wellington, New Zealand in 2017, prior to the 10th Meeting of its Advisory Committee (AC10).  Read the workshop report here.

John Cooper, Emeritus Information Officer, Agreement on the Conservation of Albatrosses and Petrels, 21 May 2024

The Ornithological Council (OC) of the Americas has unveiled its updated strategic plan. Founded in 1992, the OC brings together a network of ornithological organisations dedicated to the study and conservation of bird species across the Americas, including:

• Association of Field Ornithologists
• Birds Caribbean
• CIPAMEX: Sociedad para el Estudio y Conservación de las Aves en México
• Neotropical Ornithological Society
• North American Crane Working Group
• Pacific Seabird Group
• Raptor Research Foundation
• Waterbird Society
• Wilson Ornithological Society

The refreshed strategic plan introduces an updated mission:

1. Ensure that top-tier ornithological science informs policy, research, and management decisions impacting birds and their study.
2. Protect and enhance the professional pursuits of ornithologists.
3. Act as the unified voice of the ornithological community, increasing the impact of ornithological knowledge in public affairs.

Additionally, the plan highlights a new organizational value:

“The ornithological community recognizes the value and importance of embracing human and geographic diversity within the ornithological community and literature.”

The new strategic plan, developed with input from the entire OC board of directors, (which includes representatives of all the OC member societies) can be downloaded from the OC’s website, here.

20 May 2024  

 
A Southern Giant Petrel with the carcass of a Northern Rockhopper Penguin Eudyples moseleyi, photograph by Peter Ryan (click here for publication)

Eric Wagner (Center for Ecosystem Sentinels, Department of Biology, University of Washington, Seattle, Washington, USA) and colleagues have published open access in the journal Ecology and Evolution on an observation of Southern Giant Petrels Macronectes giganteus attacking a Magellanic Penguin Spheniscus magellanicus.

The paper’s abstract follows:

“Southern giant petrels (Macronectes giganteus) are important consumers that range across the oceans throughout the southern hemisphere.  In Argentina, previous studies have shown they eat primarily pinnipeds and penguins, which they are assumed to scavenge, although there are occasional anecdotes of them attacking living penguins.  Here we describe a predation attempt by a trio of southern giant petrels on a molting adult Magellanic penguin (Spheniscus magellanicus) at the large colony at Punta Tombo, Argentina.  We relate giant petrel attendance patterns at the colony to the penguins' phenology, showing how giant petrel numbers rise with the increasing prevalence of vulnerable penguins.  We suggest that living penguins—both fledglings and adults—may constitute a more seasonally significant proportion of the giant petrel diet than previously assumed, and their capture may represent a specialized predation technique.”

Reference:

Wagner, E.L., Rebstock, G.A. & Boersma, P.D. 2024.  A fearful scourge to the penguin colonies: Southern giant petrel (Macronectes giganteus) predation on living Magellanic penguins (Spheniscus magellanicus) may be more common than assumed.  Ecology and Evolution. 2024;14:e11258.

17 May 2024