Abundance estimation of Adélie penguins at the Esperanza/Hope Bay mega colony

Abstract

The Adélie penguin (Pygoscelis adeliae) breeding population at Esperanza/Hope Bay, at the tip of the Antarctic Peninsula, is one of the largest Adélie penguin colonies in Antarctica. Nevertheless, the last known published field count during the egg-laying period is from 1985/1986. We counted breeding pairs within the entire colony, consisting of 274 breeding groups, during the 2012/2013 breeding season for comparison with previously published ground and satellite-derived counts. We also counted breeding pairs in 26 breeding groups that have been monitored annually since 1995/1996. We estimated the current population size to be 104,139 (95th-percentile CI 70,126-138,151) breeding pairs for the whole colony. The counts indicate population declines of 15.9% over 27 years in the whole colony and 37.5% over 18 years in the annually monitored subset of breeding groups, respectively. The observed decrease matches recent trends reported in other Adélie penguin colonies throughout the western Antarctic Peninsula and southern Scotia Sea. This population assessment contributes to the current estimates of the total predator populations in the region, which is necessary information for the management of marine living resources.

Spatial and sex differences in mercury contamination of skuas in the Southern Ocean

“…Conversely, pellet analyses indicate that penguins are the dominant prey consumed at the higher latitude colonies (Signy Island and Bahía Esperanza/Hope Bay) (Burton, 1968;Graña Grilli and Montalti, 2015;Borghello et al, 2019;Ibañez et al, unpublished data), which forage in Antarctic waters (Lynnes et al, 2002). Indeed, the brown skuas at Bahía Esperanza/Hope Bay breed in close proximity to a large Adélie penguin Pygoscelis adeliae colony (approximately 100,000 breeding pairs), and two smaller gentoo penguin P. papua colonies (Santos et al, 2018;Borghello et al, 2019). Another contributing factor is that birds may undertake a pre-laying exodus after returning to the colony.…”

Update of the population size and breeding performance of gentoo penguins (Pygoscelis papua) at Stranger Point/Cabo Funes, South Shetland Islands

“…Therefore, it is valuable to update the population size of each monitored colony in order to confirm the current trends. Additionally, the update of the population size of gentoo penguins contributes to current estimates of the total predator populations in the region, which is crucial for the management and conservation of Antarctic marine living resources (Santos et al 2018).…”

Variation in blood mercury concentrations in brown skuas (Stercorarius antarcticus) is related to trophic ecology but not breeding success or adult body condition

“…Brown skuas are opportunistic predators and scavengers in both terrestrial and marine environments, feeding on a wide variety of prey (Reinhardt et al 2000;Phillips et al 2004;Ritz et al 2008;Carneiro et al 2015;Graña Grilli and Montalti 2015;Borghello et al 2019). At our study site on the Antarctic Peninsula (Esperanza/Hope Bay), brown skuas breed near numerous Adélie penguin (Pygoscelis adeliae) and gentoo penguin (Pygoscelis papua) colonies (>100,000 breeding pairs) (Santos et al 2018), and are heavily reliant on consuming carcasses, eggs and chicks, but also feed on various marine prey (fish and invertebrates) (Borghello et al 2019;Ibañez et al 2022).…”