The foraging behavior of nonbreeding Adélie penguins in the western Antarctic Peninsula during the breeding season

• Published in: Ecosphere
• Main Authors: W. Chris Oosthuizen, Pierre A. Pistorius, Malgorzata Korczak‐Abshire, Jefferson T. Hinke, Mercedes Santos, Andrew D. Lowther
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2022
• Subjects: central‐place foraging; marine predator; move persistence; nonbreeding; penguin; Pygoscelis adeliae; Ecology; QH540-549.5; Antarctic; The Antarctic; Antarctic Peninsula; Weddell Sea; King George Island; South Shetland Islands; Bransfield Strait; Weddell; Central Basin; Antarc*; Antarctica; Sea ice
• Online Access: https://doi.org/10.1002/ecs2.4090; https://doaj.org/article/2cc3ea468c294e9fa79888b37dcda78b

Abstract Information on marine predator at‐sea distributions is key to understanding ecosystem and community dynamics and an important component of spatial management frameworks that aim to identify regions important for conservation. Tracking data from seabirds are widely used to define priority areas for conservation, but such data are often restricted to the breeding population. This also applies to penguins in Antarctica, where identification of important habitat for nonbreeders has received limited attention. Nonbreeding penguins are expected to have larger foraging distributions than breeding conspecifics, which may alter their interactions with physical environmental factors, conspecifics, other marine predators, and threats. We studied the movement behavior of nonbreeding Adélie penguins tracked during the 2016/2017 breeding season at King George Island in the South Shetland Islands, Antarctica. We quantify how nonbreeding penguins' horizontal moment behavior varies in relation to environmental conditions and assess the extent of spatial overlap in the foraging ranges of nonbreeders and breeders, which were tracked over several years. Nonbreeders increased their prey search and area‐restricted foraging behavior as sea surface temperature and bottom depths decreased, and in response to increasing sea ice concentration. Nonbreeders tended to transit (high directional movement) over the relatively deep Central Basin of the Bransfield Strait. The majority of foraging behavior occurred within the colder, Weddell Sea–sourced water of the Antarctic Coastal Current (incubation) and in the Weddell Sea (crèche). The utilization distributions of breeders and nonbreeders overlapped in the central Bransfield Strait. Spatial segregation was greater during the crèche stage of breeding compared to incubation and brood, because chick provisioning still constrained the foraging range of breeders to a scale of a few tens of kilometers, while nonbreeders commenced with premolt foraging trips into the Weddell Sea. Our ...