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Foraging parameters influencing the detection and interpretation of area-restricted search behaviour in marine predators: a case study with the masked booby

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posted on 2023-05-17, 22:27 authored by Sommerfeld, Julia, Kato, A, Ropert-Coudert, Y, Garthe, S, Mark HindellMark Hindell
Identification of Area-restricted search (ARS) behaviour is used to better understand foraging movements and strategies of marine predators. Track-based descriptive analyses are commonly used to detect ARS behaviour, but they may be biased by factors such as foraging trip duration or non-foraging behaviours (i.e. resting on the water). Using first-passage time analysis we tested if (I) daylight resting at the sea surface positions falsely increase the detection of ARS behaviour and (II) short foraging trips are less likely to include ARS behaviour in Masked Boobies Sula dactylatra. We further analysed whether ARS behaviour may be used as a proxy to identify important feeding areas. Depth-acceleration and GPS-loggers were simultaneously deployed on chick-rearing adults to obtain (1) location data every 4 minutes and (2) detailed foraging activity such as diving rates, time spent sitting on the water surface and in flight. In 82% of 50 foraging trips, birds adopted ARS behaviour. In 19.3% of 57 detected ARS zones, birds spent more than 70% of total ARS duration resting on the water, suggesting that these ARS zones were falsely detected. Based on generalized linear mixed models, the probability of detecting false ARS zones was 80%. False ARS zones mostly occurred during short trips in close proximity to the colony, with low or no diving activity. This demonstrates the need to account for resting on the water surface positions in marine animals when determining ARS behaviour based on foraging locations. Dive rates were positively correlated with trip duration and the probability of ARS behaviour increased with increasing number of dives, suggesting that the adoption of ARS behaviour in Masked Boobies is linked to enhanced foraging activity. We conclude that ARS behaviour may be used as a proxy to identify important feeding areas in this species. © 2013 Sommerfeld et al.

Funding

Birds Australia

History

Publication title

PLoS ONE

Volume

8

Issue

5

Article number

e63742

Number

e63742

Pagination

1-9

ISSN

1932-6203

Department/School

Institute for Marine and Antarctic Studies

Publisher

Public Library of Science

Place of publication

USA

Rights statement

Copyright 2013 Sommerfeld et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Repository Status

  • Open

Socio-economic Objectives

Assessment and management of coastal and estuarine ecosystems

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