An estimate of the South Georgia diving petrel Pelecanoides georgicus population at Ile de la Possession, Crozet archipelago. Issue 4 (August 2020)

• Record Type: Journal Article
• Authors: Barbraud, Christophe; Chaigne, Adrien; Loubon, Maxime; Lamy, Olivier; Le Bouard, Fabrice
• Is Part Of: Antarctic science. Volume 32:Issue 4(2020)
• Page Start: 248
• Page End: 254
• Publication Date: 2020-08
• Subjects: acoustic playback, -- burrowing petrel, -- detection probability, -- distance sampling, -- Procellariiformes; Science -- Antarctica -- Periodicals; 509.989
• DOI: 10.1017/S095410202000019X
• Languages: English
• ISSNs: 0954-1020

Abstract

Abstract: 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.