A White-chinned Petrel among tussac on Top Island, photograph by Kalinka Rexer-Huber

Amanda Kuepfer (Falklands Conservation) and colleagues have published a report of a survey of Vulnerable and ACAP-listed White-chinned Petrels Procellaria aequinoctialis and of Sooty Shearwaters Ardenna grisea on two islands, Kidney and Top, within the Falkland Islands (Islas Malvinas)*. The research was undertaken to “fulfil international commitments under the Agreement on the Conservation of Albatrosses and Petrels (ACAP) to monitor and manage ACAP breeding sites.”

The survey results from the summary follow:

“Kidney Island 2023/2024

- Sooty shearwater population size = 131,000 (95% CI: 95,000 – 176,000) breeding pairs.  This estimate is not notably different from 2016 (123,000; 95% CI: 87,000 – 167,000 breeding pairs), and gives no strong indication of an important increase or decrease in breeding pairs at this site.

- White-chinned petrel population size = 331 (95% CI: 52 – 1043) breeding pairs.  This represents a baseline estimate using a model-based approach.

Top Island 2023/2024

- Sooty shearwater population size = 12,000 (95% CI: 7,000 – 19,000) breeding pairs.  This represents a baseline estimate.

- White-chinned petrel population size = 199 (95% CI: 33 – 594) breeding pairs. This represents a baseline estimate”.

The summary ends with management recommendations:

“Sooty shearwaters were found in greater numbers in areas with dense tussac over peat, while white-chinned petrels were most numerous in areas of tussac peat with higher moisture content.  Additionally, like most burrowing seabirds, these species are susceptible to invasive mammals and other non-native species due to predation and habitat loss.  Effective site management for sooty shearwater and white-chinned petrels should focus on preserving healthy tussac habitat, maintaining suitable peat condition for burrowing, and ensuring the continued absence of invasive mammals.  Biosecurity efforts should further aim to minimise the risk of introducing invasive plants, invertebrates and pathogens.  Additional monitoring efforts to further refine population estimates and track habitat availability could be considered.”

Read an earlier article in ACAP Latest News on the surveys here.

Reference:

Kuepfer, A., Lee, B. & Stanworth, A. 2024.  Burrowing Seabird Survey 2023/2024: Population Estimates of Sooty Shearwaters and White-chinned Petrels on Kidney Island and Top Island, Falkland Islands.  Stanley: Falklands Conservation.  50 pp.

John Cooper, Emeritus Information Officer, Agreement on the Conservation of Albatrosses and Petrels, 10 December 2024

*A dispute exists between the Governments of Argentina and the United Kingdom of Great Britain and Northern Ireland concerning sovereignty over the Falkland Islands (Islas Malvinas), South Georgia and the South Sandwich Islands (Islas Georgias del Sur y Islas Sandwich del Sur) and the surrounding maritime areas.

Northern Fulmar at sea

Susanne Kühn and Jan van Franeker (Wageningen Marine Research, Den Helder, the Netherlands) have written to ACAP Latest News on the findings of their lab’s long-standing work on plastic pollution in Northern Fulmars Fulmarus glacialis during 2023:

“In 2023 a total of 32 corpses could be recovered, of which 26 contained an intact stomach.  In addition we report on 6 birds found in 2021 and 2022 (5 with stomach) that arrived in our lab too late for inclusion in our earlier reports.  In order to avoid unstable annual variations, we always describe the ‘current situation’ in our monitoring analyses as the average over the past five years.  From 2019 to 2023 we studied a total of 231 stomachs of which 94% contained plastics, and 53% contained more than 0.1 g of plastic.  The international policy target is that this latter percentage has to be reduced to under 10%.  The average fulmar stomach currently contains 24 plastic particles, weighing 0.27 g.  Measured over the past 10 years, we cannot document a significant decline in ingested plastic mass.  However, the longer term trend 2002-2023 of annual proportions of birds exceeding the 0.1g level, does show a significant decline (p=0.027) predicting that the 10% policy target might be reached around the year 2087.”

A belly full of plastic

“More than 9 our of 10 beachwashed Northern Fulmars has plastic in the stomach.  Usually it concerns smaller quantities of some tenths of grams of plastic.  However, some birds have so much plastic in the stomach that at opening of the corpse the litter is immediately evident. This short video illustrates the exceptional [record] of a fulmar found during 2022 in the Netherlands”.

In 2023, ACAP adopted the theme of “Plastic Pollution” to mark World Albatross Day on 19 June.

With thanks to Susanne Kühn and Jan van Franeker, Wageningen Marine Research.

References:

Kühn, S., Meijboom, A., Bittner, O. & Van Franeker, J.A. 2024.  Fulmar Litter Monitoring in the Netherlands – Update 2023.  Wageningen Marine Research Report C042/24 and RWS Centrale Informatievoorziening Report BM 24.15.  Den Helder, The Netherlands. 54 pp.

Van Franeker, J.A., Kühn, S., Meijboom, A. & Bittner, O. 2024.  Fulmar Finders Information - Netherlands 2023.  Den Helder, The Netherlands:Wageningen Marine Research.  48 pp.

John Cooper, Emeritus Information Officer, Agreement on the Conservation of Albatrosses and Petrels, 09 December 2024

"Feeding sequence of a Northern Giant Petrel on the carcass of a conspecific chick at the colony of Petit Caporal, Possession Island, on 3 December 2021.   (a) Adults seen near the carrion at the beginning of our observation.  Ringed adult in the background showed agonistic behavior toward the closest adult. (b) Closest adult, with a monel ring on the left leg, approaching the chick with wings spread.  (c) Same adult dragging the carrion to feed on it.  (d) The adult tears off some flesh, showing the typical behavior of a scavenging giant petrel. (e) Carrion of the Northern Giant Petrel chick. The bill tip of the chick shows the typical red color of the Northern Giant Petrels.  Photo credits: Florent Sabatier". {Figure 1 from the publication)

Alexandre Vong (Centre d'Etudes Biologiques de Chizé, Villiers en Bois, France) and colleagues have published open access in the journal Ecology on instances of cannibalism observed in Northern Giant Petrels Macronectes halli.

Their short paper concludes:

“We showed here with multiple records that cannibalism is clearly part of the feeding behavior of northern [giant] petrels and partly explains the occurrence of breeding failures at Possession Island.  Further research is needed to fully understand the role of cannibalism in the feeding repertoire of giant petrels and to identify the drivers underlying this behavior.”

With thanks to Karine Delord.

Reference:

Vong, A., Delord, K., Croizé, N., Lesage, C., Zubiri, L.L., Sabatier, F. & Barbraud, C, 2024.  Cannibalism in northern giant petrels (Macronectes halli) at Possession Island, Southern Indian Ocean.  Ecology doi.org/10.1002/ecy.4491.

06 December 2024

This graphical abstract shows how DNA sequencing can help discriminate between seabird species caught as bycatch, compared to visual methods of identification. Different parts of seabirds' genomes have sequences that are specific to each species, which can be targeted with the right DNA markers. Graphical abstract illustrated by Stacey McCormack [Visual Knowledge Pty Ltd] and supplied by Andrea Polanowski 

Andrea Polanowski (Australian Antarctic Division, Department of Climate Change, Energy, The Environment and Water, Australia) and colleagues have published open access in the journal Ecology and Evolution on the use of DNA in identifying seabird bycatch.

The paper’s abstract follows:

“Incidental mortality in fisheries is a major driver of population declines for albatrosses and petrels globally. However, accurate identification of species can be difficult due to the poor condition of bycaught birds and/or visual similarities between closely related species. We assessed three genetic markers for their ability to distinguish the 36 albatross and petrel species listed in Annex 1 to the Agreement on the Conservation of Albatrosses and Petrels (ACAP) and in Australia's Threat Abatement Plan (TAP) for the bycatch of seabirds during oceanic longline fishing operations. We generated 275 new sequences, from 29 species, to improve the coverage of reference databases for these listed species. The combined use of the selected Cytochrome b and Control Region markers enabled the identification of 31 of 36 listed seabirds to species level and four to sister species. One petrel species could not be evaluated as no reference sequences were available. We tested these markers on 59 feathers from bycaught seabirds and compared these to onboard visual identification. We successfully assigned all procellariiforms to species (n = 58), whereas only two seabirds were correctly identified to species visually onboard, highlighting the difficulty of visual species assignment and the need for alternative methods. We assessed the utility of our two chosen markers for the assignment of all procellariiform species, with 74% of species with reference sequences identified to species or sister species level. However, a precautionary approach is needed for application beyond our listed species due to unvalidated reference sequences. The approach described here provides a streamlined framework for the molecular identification of seabird bycatch. This approach is recommended for use in fisheries within and outside Australian waters to improve the resolution of bycatch reporting and to corroborate logbook entries, observer reports and audits of images captured by electronic monitoring systems as well as help inform conservation efforts.”

Reference:

Polanowski, A.M., MacDonald, A.J., Double, M.C., Barrington, J.H.S., Burg, T.M., Wienecke, B. & McInnes, J.C. 2024. The development of DNA markers to resolve uncertainties of seabird bycatch identification from longline fisheries in Australian waters.  Ecolology and Evolution 14: e70568.

05 December 2024