Breeding Ecology of Adélie Penguins in Mid Victoria Land, Ross Sea Antarctica

Abstract

Identifying the factors influencing seabird breeding output is critical for their conservation because breeding performance in turn influences population dynamics. This is particularly important in sensitive environments, where ecological disturbances can lead to changes in population trends of extremely specialized species in a relatively short time. Here, we have reported on the breeding output of the Adélie penguin Pygoscelis adeliae in three colonies of the Mid Victoria Land, Ross Sea (Antarctica), in 2017/2018–2018/2019 to provide scientific information for the Ross Sea Marine Protected Area research and management plan. Breeding chronology, breeding success and chick growth did not differ between study colonies and were in line with data reported for other penguin colonies across Antarctica. Penguin breeding success was higher in central than in peripheral nests and decreased with an increasing number of neighboring nesting skuas; conversely, at-nest weather conditions experienced by chicks did not seem to play a role. Our findings suggest that the quality of the nesting environment seems more important than the general condition of the colony in determining breeding output. Therefore, along with marine habitat characteristics for the planning of management and conservation of seabirds, the importance of the terrestrial environment must be also duly considered.

Living in a Challenging Environment: Monitoring Stress Ecology by Non-Destructive Methods in an Antarctic Seabird

“…Peripheral nests have been described as higher effort/cost maintenance, since more individuals attempt to steal stones, thus increasing intraspecific competition (Tenaza, 1971;Morandini et al, 2021). Also, peripheral nests are more susceptible to skua's attacks and predations (see Olmastroni et al, 2022, for our study colonies), and their occupants are both subject to stress due to interspecific and intraspecific competition (Giese, 1996; but see also Spurr, 1974).…”

“…While InIs and AdCo are affected by katabatic winds, EdPo is generally not affected and is characterised by several kilometres of fast ice that remain in place until late February. The three colonies markedly differ in relation to the number of breeding penguins, being greater at InIs, intermediate at AdCo, and smaller at EdPo (~29,000, 13,400, and ~2700 breeding pairs, respectively;www.penguinmap.com 27/11/ 2023;Olmastroni et al, 2022). Marine (leopard seal Hydrurga leptonyx, killer whales Orcinus orca) and terrestrial (south polar skua Stercorarius maccormicki) predators of penguins occur in all colonies, but skua density per penguin nest differs substantially between colonies, being higher at EdPo, intermediate at AdCo and lower at InIs (Olmastroni et al, 2022).…”

“…The three colonies markedly differ in relation to the number of breeding penguins, being greater at InIs, intermediate at AdCo, and smaller at EdPo (~29,000, 13,400, and ~2700 breeding pairs, respectively;www.penguinmap.com 27/11/ 2023;Olmastroni et al, 2022). Marine (leopard seal Hydrurga leptonyx, killer whales Orcinus orca) and terrestrial (south polar skua Stercorarius maccormicki) predators of penguins occur in all colonies, but skua density per penguin nest differs substantially between colonies, being higher at EdPo, intermediate at AdCo and lower at InIs (Olmastroni et al, 2022). For further details on marine and terrestrial habitat characteristics in the three study areas, see Mori et al (2021).…”

“…The collection of blood samples occurred along with different research activities conducted in the framework of the PenguinERA project (Olmastroni et al, 2022). To reduce the stress of capture and manipulation, penguins were gently lifted from their nests and covered with a hood, while eggs and/or chicks were protected and kept warm during handling.…”