Figure 1. Schematic of a wandering albatross flying in an across-wind direction using an S-shaped dynamic soaring manoeuvre consisting of a series of upwind and downwind turns through the boundary layer (redrawn after Sachs [6]). The bird extracts mechanical energy from the wind by climbing headed upwind and descending headed downwind. Wave heights are typically large in the Southern Ocean. Wind–wave interactions cause a more complicated instantaneous wind field than the average shown here, and waves themselves induce updrafts. Albatrosses appear to efficiently exploit these fine-scale variations in wind velocity, making modelling their flight challenging. 

Philip Richardson (Department of Physical Oceanography, Woods Hole Oceanographic Institution, USA) and Ewan Wakefield have published open access in the journal Royal Society Open Science an analysis of the wandering albatrosses’ utilisation of dynamic soaring using GPS tracking data and model simulations.

The paper’s abstract follows:

Wandering albatrosses exploit wind shear by dynamic soaring (DS), enabling rapid, efficient, long-range flight. We compared the ability of a theoretical nonlinear DS model and a linear empirical model to explain the observed variation of mean across-wind airspeeds of GPS-tracked wandering albatrosses. Assuming a flight trajectory of linked, 137° turns, a DS cycle of 10 s and a cruise airspeed of 16 m s⁻¹, the theoretical model predicted that the minimum wind speed necessary to support DS is greater than 3 m s⁻¹. Despite this, tracked albatrosses were observed in flight at wind speeds as low as 2 m s⁻¹. We hypothesize at these very low wind speeds, wandering albatrosses fly by obtaining additional energy from updrafts over water waves. In fast winds (greater than 8 m s⁻¹), assuming the same 10 s cycle period and a turn angle (TA) of 90°, the DS model predicts mean across-wind airspeeds of up to around 50 m s⁻¹. In contrast, the maximum observed across-wind mean airspeed of our tracked albatrosses reached an asymptote at approximately 20 m s⁻¹. We hypothesize that this is due to birds actively limiting airspeed by making fine-scale adjustments to TAs and soaring heights in order to limit aerodynamic force on their wings.

An article explaining the paper’s findings has been released by Woods Hole Oceanographic Institution (WHOI) on their website.

Reference:

Richardson P.L. and Wakefield E.D. 2022 Observations and models of across-wind flight speed of the wandering albatross Royal Society Open Science. 9211364211364 http://doi.org/10.1098/rsos.211364

12 December 2022

ACAP Secondee Maximiliano Hernandez (right) with Dragonfly's Environmental Data Scientist, Yvan Richard (left); photograph courtesy of Sarah Wilcox

There may have been a delay of two-years for Argentinian Maximiliano Hernandez to complete his secondment developing an Ecological Risk Assessment within a framework of seabird conservation, but from his perspective, it was worth the wait. Maximiliano had initially planned for the secondment to take place in November 2020, however the COVID-19 pandemic put his travel to New Zealand on hold.

Maximiliano is a PhD student at the Institute of Marine and Coastal Research, National University of Mar del Plata in Argentina, and is interested in the development of Ecological Risk Assessments specific to species known to interact with Argentinian fisheries, which includes a number of ACAP-listed species. 

His successful application to ACAP’s Secondment Programme in 2019 included the New Zealand Department of Conservation facilitating opportunities for Maximiliano to work with experts in ecological risk assessment whilst ACAP provided funding for travel and living expenses during the proposed project. 

A Black-browed Albatross - one of the first species, alongside the White-chinned Petrel, Maximiliano chose for his first assessments due to the abundance of population data and their high catch rates in Argentinian fisheries; photograph by Maximiliano Hernandez

Maximiliano was afforded the opportunity to work under the guidance and expertise of Dr Yvan Richard, an Environmental Data Scientist with Wellington-based company, Dragonfly Data Science. Yvan has over 10 years’ experience in carrying out Ecological Risk Assessments and introduced Maximiliano to several programming tools used to write code for the assessments, skills which will benefit not just Maximiliano but his Argentinian colleagues on his return. The results of the analyses will contribute to the effective implementation of Argentine NPOA-Seabirds.

Capacity building through the fostering of collaboration and knowledge-sharing between Parties are key tenets that underpin the philosophy of the ACAP Secondment Programme. The ACAP Secretariat is delighted to finally report on the successful completion of Maximiliano’s secondment, which highlights how a collaborative approach between Parties serves the Agreement in striving toward its central purpose - to improve conservation outcomes for all ACAP-listed species.

Read more about Maximiliano and his time spent with Yvan Richard in Dragonfly’s article on the project by Sarah Wilcox (link). 

9 December 2022

Balearic Shearwater by Anju Rajesh, after a photograph by 'Pep' Arcos

Joan Ferrer Obiol (Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Spain) and colleagues have published open access in the journal Molecular Phylogenetics and Evolution, finding that current taxonomies do not provide an accurate delineation of North Atlantic and Mediterranean Puffinus shearwaters.  Based on their genetic study, they propose Yelkouan and Balearic P. mauretanicus Shearwaters should not be given specific status but be regarded as subspecies of the Mediterranean Shearwater P. yelkouan.

The authors state that the two taxa “are good examples of differentiated populations worthy of consideration as intraspecific units that represent unique morphological, ecological and genetic diversity for conservation of biodiversity.  We stress that developing action plans for P. mauretanicus and P. yelkouan should not depend on whether these taxa are classified as separate species or not.”

A  banded Yelkouan Shearwater in Malta, photograph by Andre Raine

The paper’s abstract follows

“Speciation is a continuous and complex process shaped by the interaction of numerous evolutionary forces. Despite the continuous nature of the speciation process, the implementation of conservation policies relies on the delimitation of species and evolutionary significant units (ESUs).  Puffinus shearwaters are globally distributed and threatened pelagic seabirds. Due to remarkable morphological status the group has been under intense taxonomic debate for the past three decades. Here, we use double digest Restriction-Site Associated DNA sequencing (ddRAD-Seq) to genotype species and subspecies of North Atlantic and Mediterranean Puffinus shearwaters across their entire geographical range. We assess the phylogenetic relationships and population structure among and within the group, evaluate species boundaries, and characterise the genomic landscape of divergence. We find that current taxonomies are not supported by genomic data and propose a more accurate taxonomy by integrating genomic information with other sources of evidence. Our results show that several taxon pairs are at different stages of a speciation continuum. Our study emphasises the potential of genomic data to resolve taxonomic uncertainties, which can help to focus management actions on relevant taxa, even if they do not necessarily coincide with the taxonomic rank of species.”

Read an ACAP Monthly Missive on listing more shearwaters on the Agreement, including the Yelkouan, here.

Reference:

Species delimitation using genomic data to resolve taxonomic uncertainties in a speciation continuum of pelagic seabirds.  Molecular Phylogenetics and Evolution  179.  doi.org/10.1016/j.ympev.2022.107671.

John Cooper, ACAP News Correspondent, 08 December 2022

Salvin's Albatross; photograph by Matt Charteris & Black Petrel; photograph by Virginia Nicol

Johannes H. Fischer (Department of Conservation, Wellington, New Zealand) and colleagues have published in the journal, Bird Conservation International on the occurrence and distribution of Vulnerable Black Petrels Procellaria parkinsoni and Salvin’s Albatrosses Thalassarche salvini in Peruvian waters.

The paper’s summary in both English and Spanish follows:

Summary

Seabirds are highly threatened, including by fisheries bycatch. Accurate understanding of offshore distribution of seabirds is crucial to address this threat. Tracking technologies revolutionised insights into seabird distributions but tracking data may contain a variety of biases. We tracked two threatened seabirds (Salvin’s Albatross Thalassarche salvini n = 60 and Black Petrel Procellaria parkinsoni n = 46) from their breeding colonies in Aotearoa (New Zealand) to their non-breeding grounds in South America, including Peru, while simultaneously completing seven surveys in Peruvian waters. We then used species distribution models to predict occurrence and distribution using either data source alone, and both data sources combined. Results showed seasonal differences between estimates of occurrence and distribution when using data sources independently. Combining data resulted in more balanced insights into occurrence and distributions, and reduced uncertainty. Most notably, both species were predicted to occur in Peruvian waters during all four annual quarters: the northern Humboldt upwelling system for Salvin’s Albatross and northern continental shelf waters for Black Petrels. Our results highlighted that relying on a single data source may introduce biases into distribution estimates. Our tracking data might have contained ontological and/or colony-related biases (e.g. only breeding adults from one colony were tracked), while our survey data might have contained spatiotemporal biases (e.g. surveys were limited to waters <200 nm from the coast). We recommend combining data sources wherever possible to refine predictions of species distributions, which ultimately will improve fisheries bycatch management through better spatiotemporal understanding of risks.

Resumen

Las aves marinas están seriamente amenazadas, incluyendo por capturas incidentales en diversas pesquerías. La distribución espacial precisa de aves marinas en zonas oceánica es crucial para hacer frente a estas amenazas. Las tecnologías de seguimiento satelital revolucionaron la información sobre las distribuciones espaciales de aves marinas, pero estos datos pueden contener diversos sesgos. Rastreamos dos aves marinas amenazadas (Albatros de Salvini Thalassarche salvini n = 60 y Petrel Negro Procellaria parkinsoni n = 46) desde sus colonias reproductivas en Aotearoa (Nueva Zelanda) hacia zonas oceánicas de Sudamérica, incluyendo Perú, durante su periodo post reproductivo 2018–2020, de manera simultánea se realizaron siete cruceros científicos de avistamientos de aves marinas en aguas peruanas. Luego se utilizaron variables ambientales y modelos de distribución de especies para predecir su ocurrencia y distribución utilizando una de las fuentes de datos o ambas en combinación. Los resultados muestran diferencias estacionales entre las estimaciones de ocurrencia y distribución cuando se utiliza una sola fuente de datos. Sin embargo, cuando se combinaron ambas fuentes de datos, se obtuvo un resultado mucho más equilibrado con respecto a la ocurrencia y distribución de las especies evaluadas, con una notable disminución del sesgo. En particular, se predijo que ambas especies ocurrirían en aguas peruanas durante todas las estaciones. Donde el Albatros de Salvini se distribuye en Ecosistema de la Corriente de Humboldt, y el Petrel negro en la zona de la plataforma continental al norte del país. Nuestros resultados resaltan que confiar en una sola fuente de datos puede generar un mayor sesgo en las estimaciones de distribución. Nuestros datos de seguimiento satelital podrían tener sesgos ontológicos y/o relacionados al grupo etareo evaluado en las colonias reproductivas (solo se rastrearon a aves adultas), mientras que nuestros datos de avistamientos a bordo de embarcaciones en Perú, tienen sesgos espaciotemporales (por ejemplo, las evaluaciones se limitaron a aguas <200 nm de la costa). Recomendamos usar ambas fuentes de datos en conjunto, siempre que sea posible, para poder tener una predicción más precisa y fina en la distribución de estas aves marinas, esta información será fundamental para una mejor gestión en el manejo de estas pesquerías para mitigar las capturas incidentales de estas especies a través de una adecuada comprensión de los riesgos a escalas espacio temporales.

Reference:

Fischer, J., Bose, S., Romero, C., Charteris, M., Crowe, P., Parker, G., . . . Quiñones, J. (2022). Combining tracking with at-sea surveys to improve occurrence and distribution estimates of two threatened seabirds in Peru. Bird Conservation International, 1-12. https://doi.org/10.1017/S0959270922000442

December 7 2022