Group foraging of Gentoo and Chinstrap penguins in King George Island, Antarctica

Abstract

Being in a group provides advantages for prey searching and catching, especially when the food source is heterogeneously distributed. Penguins are highly dependent on krill, which often form large swarms. Thus, group foraging for krill can increase foraging efficiency of individuals. Using animal-borne cameras on 28 gentoo penguins (Pygoscelis papua), we recorded their foraging behavior during chick guarding in two breeding seasons (2014-2015 and 2015-2016). We found that gentoo penguins mostly foraged on Antarctic krill, Euphausia superba (99.9%) and often forage with multiple conspecifics (36.16% among 1449 foraging diving events). When foraging in groups, individuals had higher capture rate per dive (average 21.05 krill per dive) than that of solitary foraging (average 14.75 krill per dive). Our results suggest that gentoo penguins in our population have group foraging strategies and benefit from increased foraging success.