Marine Biology

, 149:139

Foraging strategies and prey encounter rate of free-ranging Little Penguins

  • Yan Ropert-Coudert
  • Akiko Kato
  • Rory P. Wilson
  • Belinda Cannell
Research Article

DOI: 10.1007/s00227-005-0188-x

Cite this article as:
Ropert-Coudert, Y., Kato, A., Wilson, R.P. et al. Marine Biology (2006) 149: 139. doi:10.1007/s00227-005-0188-x

Abstract

There is little information on the effort put into foraging by seabirds, even though it is fundamental to many issues in behavioural ecology. Recent researchers have used changes in the underwater cruising speed of penguins to allude to prey ingestion since accelerations are thought to reflect the encounter and pursuit of prey. In this study, we attached minute accelerometers, to determine flipper beat frequency as a proxy for prey pursuit, to Little Penguins Eudyptula minor foraging in shallow waters in Western Australia. During diving, Little Penguins flapped continuously and at a regular pace of 3.16 Hz while descending the water column and throughout the bottom phase of most dives. However, the frequency and amplitude of wingbeats increased transitorily, reaching 3.5–5.5 Hz, during some dives indicating prey pursuit. Pursuit phases lasted a mean of 2.9±3.3 s and occurred principally during the bottom phases of dives (75.4%). Most dives in all birds (86%) had a clear square-shaped depth profile indicating feeding activity near the seabed in the shallow waters of the bays. Hourly maximum depth, time spent underwater, percentage of dives with pursuit events and catch per unit effort showed an overall increase from zero at ca. 0500 h to a maximum during the hours around mid-day before decreasing to zero by 1900 h. During pursuit phases, Little Penguins headed predominantly downward, probably using the seabed to assist them in trapping their prey. In the light of our results, we discuss depth use by Little Penguins and their allocation of foraging effort and prey capture success as a function of environmental conditions.

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Yan Ropert-Coudert
    • 1
  • Akiko Kato
    • 1
  • Rory P. Wilson
    • 2
  • Belinda Cannell
    • 3
  1. 1.National Institute of Polar ResearchTokyoJapan
  2. 2.School of Biological SciencesUniversity of Wales-SwanseaSwanseaUK
  3. 3.Murdoch UniversityPerthAustralia