Serendipitous observations from animal-borne video loggers reveal synchronous diving and equivalent simultaneous prey capture rates in chinstrap penguins

Jefferson T Hinke,Tamara M Russell,Victoria R Hermanson,Laura Brazier,Stephanie L Walden

doi:10.1007/s00227-021-03937-5

Abstract

Seabirds often engage in coordinated, cooperative foraging to improve detection and capture of prey. An extreme example of such coordinated behavior is synchronicity, whereby the movements of individuals are aligned temporally and spatially. Synchronous diving among penguins has been reported, but simultaneous observations of predation by synchronously diving individuals have not. We instrumented chinstrap penguins (Pygoscelis antarcticus) during their incubation period in December 2019 from Cape Shirreff, Livingston Island, Antarctica (60.79°W, 62.46°S) with video and depth recorders to monitor predator foraging behavior and prey consumption rates. Serendipitously, two instrumented individuals, accompanied by a third, banded individual, engaged in synchronous foraging activities on Antarctic krill (Euphausia superba) for 9.25 h. This group formed ashore, transited together to their foraging area, remained in close visual contact after dives, synchronously timed diving behavior, and foraged at similar depths. Prey capture rates were positively correlated across dives and total consumption estimates were equivalent for the two instrumented birds during the video observation period. Video loggers confirmed that synchronous diving and foraging behavior are among the behavioral repertoire of chinstrap penguins and demonstrated equivalent prey capture rates by synchronously foraging predators. The results further suggest that group formation while ashore and group cohesion during a foraging trip may facilitate shared foraging success among group members.

Highlights

Seabirds often engage in group hunting to improve detection and capture of dense, but patchy, prey resources (Götmark et al 1986; Ballance and Pitman 1999; Sutton et al 2015; McInnes et al 2017)
Chinstrap penguins at Cape Shirreff have been monitored by the United States Antarctic Marine Living Resources Program (U.S AMLR) since 1996/97, during which time breeding populations have declined from 7744 breeding pairs in 1997/98 to 2170 breeding pairs in 2019/20
The video loggers initiate recording based on pre-set timers that were configured to delay recording for several hours after release and to record continuously until battery exhaustion

Summary

Introduction

Seabirds often engage in group hunting to improve detection and capture of dense, but patchy, prey resources (Götmark et al 1986; Ballance and Pitman 1999; Sutton et al 2015; McInnes et al 2017). An extreme example of such coordinated hunting behavior is synchronicity, whereby the movements of individual predators in a group are aligned temporally and spatially. Data from animal-borne sensors demonstrated that synchrony extended beyond the timing of dives to include similar dive profiles among individuals in several species (Tremblay and Cherel 1999; Takahashi et al 2004b; Pütz and Cherel 2005; Berlincourt and Arnould 2014; Wantanabe and Takahashi 2013). Synchronous diving behavior of conspecifics may indicate complex cooperative foraging strategies that benefit all group members (Tremblay and Cherel 1999). The degree of coordination necessary for prey capture, can vary among predator species and be affected by the distribution

Methods

Results

Discussion

Conclusion