10.5061/DRYAD.KWH70RZ0T
Collet, Julien
0000-0002-3285-5535
Centre d'Etudes Biologiques de Chizé
Prudor, Aurélien
Centre d'Etudes Biologiques de Chizé
Corbeau, Alexandre
Centre d'Etudes Biologiques de Chizé
Mendez, Loriane
Centre d'Etudes Biologiques de Chizé
Weimerskirch, Henri
Centre d'Etudes Biologiques de Chizé
First explorations: ontogeny of central-place-foraging directions in two
tropical seabirds
Dryad
dataset
2020
Post-fledging juveniles
Homing efficiency
Colonial birds
GPS tracking
Wind use
Individual foraging consistency
Fregata minor
Sula sula
Foraging trip directions
Europa Island
European Research Council
https://ror.org/0472cxd90
ERC-2012-ADG_20120314
French National Centre for Scientific Research
https://ror.org/02feahw73
Iles Eparses
Institut de Recherche pour le Développement
https://ror.org/05q3vnk25
Iles Eparses
Agence des Aires Marines Protégées
https://ror.org/03qps9x60
Iles Eparses
Ministry of Higher Education and Research
https://ror.org/03sjk9a61
Facteurs influnçant les stratégies de recherche de nourriture des
oiseaux marins
2020-03-06T00:00:00Z
2020-03-06T00:00:00Z
en
BEHECO-2019-0209
835855 bytes
1
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
A widespread hypothesis for the ontogeny of behaviour and decision-making
is the early-exploration-later-canalization hypothesis. It postulates that
juveniles are more exploratory and adults more consistent in their
behavior. In addition, it is often assumed that naïve juveniles could
overcome the costs of individual experience building by copying more the
decisions of others than adults (early-conformism-later-self-defining
hypothesis). Here we compare the central-place-foraging movements of
adults and post-fledging juveniles in their first flights around the
colony before dispersal and migration, in two sympatric species of
tropical seabirds: red-footed boobies and great frigatebirds. Using GPS
records of individual movements, we analyzed the foraging directions of
seabirds from the colony across successive trips. Juveniles of both
species showed significant within-individual consistency in foraging
direction but at lower levels than adults. Juveniles leaving the colony
within the same time-window showed significant but low between-individual
resemblance in foraging direction, at levels similar to adults. In both
species, homing efficiency was lower in juveniles than in adults. Juvenile
foraging directions were initially influenced by wind conditions,
particularly in low-wing-loading frigatebirds. Wind conditions
progressively lost influence on juvenile foraging directions during their
first weeks of flights. In contrast within-individual consistency,
between-individual resemblance and homing efficiency did not show signs of
progression in juveniles. Our results support the
early-exploration-later-canalization hypothesis but not the
early-conformism-later-self-defining hypothesis. Relaxed constraints on
self-feeding efficiency could favour high variability in post-fledging
tropical seabirds. Our simple approach could be applied to further test
these hypotheses by comparing strategies across a wide range of
central-place foragers.
Birds were captured on nest and fitted with GPS-data loggers with adhesive
tape. From the GPS tracks we identified each single foraging excursions
from the colony, each one corresponds to one row in the provided dataset
(TripMetadata.csv). For each foraging trip we extracted statitistics such
as the distance and direction from colony along diverse points of the
track: maximum range from colony, different % of the maximum range from
colony on both the way out and the way in, or the first point reaching 10,
20, etc. km from the colony both on the way out and the way in. From each
of these points we also extracted a standardized straightness index.
Finally we also added information on wind (u,v as available from NOAA
servers, but also transformed into other referentials e.g. wind direction
and speed (polar referential) or in parallel/perpendicular to flight
direction referential. See M&M for more details on data collection
and the analyses reported in the manuscript. All analyses presented can be
replicated following the script StatisticalAnalyses&Figures.R, as
well as all figures except for Fig1 which requires original tracking data.
Notably, analyses on resemblance call on two specific scripts to establish
resemblance between all possible pairs of trips (for juv and ad,
respectively). Sensitivity analyses can be carried by changing parameter
values, or in the case of changing the definition of trip directions (e.g.
first 10km) by using the script DirectionAt10km.