poupart-foragingnicheoverlap-2020.pdf (1.13 MB)
Download file

Foraging niche overlap during chick-rearing in the sexually dimorphic Westland petrel

Download (1.13 MB)
journal contribution
posted on 2020-11-25, 00:00 authored by Timothee Poupart, S M Waugh, A Kato, John ArnouldJohn Arnould

Most Procellariform seabirds are pelagic, breed in summer when prey availability peaks, and migrate for winter. They also display a dual foraging strategy (short and long trips) and sex-specific foraging. The Westland petrel
Procellaria westlandica
, a New Zealand endemic, is one of the rare seabirds breeding in winter. Preliminary findings on this large and sexually dimorphic petrel suggest a foraging behaviour with no evidence of a dual strategy, within a narrow range and with shared areas between sexes. To investigate further this unusual strategy, the present study determined the fine-scale at-sea behaviours (global positioning system and accelerometer data loggers) and trophic niches (stable isotopes in whole blood) of chick-rearing individuals (16 males and 13 females). All individuals foraged on the shelf-slope of the west coast of New Zealand's South Island with short, unimodal trips. Both sexes foraged at similar intensity without temporal, spatial or isotopic niche segregation. These findings suggest the presence of a winter prey resource close to the colony, sufficient to satisfy the nutritional needs of breeding without increasing the foraging effort or intra-specific competition avoidance during winter. Additional data are needed to assess the consistency of foraging niche between the sexes and its reproductive outcomes in view of anticipated environmental changes.

History

Journal

Royal Society Open Science

Volume

7

Issue

11

Article number

191511

Pagination

1 - 17

Publisher

Royal Society

Location

London, Eng.

ISSN

2054-5703

eISSN

2054-5703

Language

English

Publication classification

C Journal article; C1 Refereed article in a scholarly journal

Copyright notice

2020, The Authors