An estimate of the South Georgia diving petrel Pelecanoides georgicus population at Ile de La Possession, Crozet archipelago

• Published in: Antarctic Science
• Main Authors: Barbraud, Christophe, Chaigne, Adrien, Loubon, Maxime, Lamy, Olivier, Le Brouard, Fabrice
• Other Authors: Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Réserve Naturelle Nationale des Terres Australes Françaises
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: acoustic playback; burrowing petrel; detection probability; distance sampling; Procellariiformes; [SDE]Environmental Sciences; Burrows; Indian; Antarctic Science
• Online Access: https://hal.science/hal-03023636; https://doi.org/10.1017/S095410202000019X

International audience Burrow-nesting seabirds constitute an important part of seabird diversity, yet accurate estimates of their abundance are largely lacking, limiting our understanding of their population dynamics and conservation status. We conducted a survey to estimate the number of South Georgia diving petrel (Pelecanoides georgicus) burrows during the 2013–14 breeding season on Ile de la Possession, Crozet archipelago, southern Indian Ocean. We used distance sampling and acoustic playback in order to estimate burrow densities in a priori-selected favourable nesting areas. A total of 855 burrows were detected. The mean altitude of burrows was 601.8 ± 69.4 m. The mean burrow detection distance was 1.77 ± 1.63 m. The burrow density was estimated at 15.649 burrows ha-1 (95% confidence interval (CI): 10.245–23.903) and the slope-corrected total favourable area was 2365.53 ha, which yielded an estimate 37 018 burrows (95% CI: 24 235–56 544). The playback response rate was 15.8 ± 1.3%, and 40.8 ± 1.7% of burrows were occupied or showed signs of occupation. Occupancy rates were low compared to those measured by systematic burrow inspection in other studies. Assuming that laying occurred in 80–93% of the estimated number of burrows, as estimated by previous studies, gives an estimate of 29 614 (95% CI: 19 388–45 235) to 34 426 (95% CI: 22 538–52 585) breeding pairs.