Early-life foraging: Behavioral responses of newly fledged albatrosses to environmental conditions
Résumé
In order to survive and later recruit into a population, juvenile animals need to acquire
resources through the use of innate and/or learnt behaviors in an environment new to
them. For far-ranging
marine species, such as the wandering albatross Diomedea exulans,
this is particularly challenging as individuals need to be able to rapidly adapt and
optimize their movement strategies in response to the highly dynamic and heterogeneous
nature of their open-ocean
pelagic habitats. Critical to this is the development
and flexibility of dispersal and exploratory behaviors. Here, we examine the movements
of eight juvenile wandering albatrosses, tracked using GPS/Argos satellite
transmitters for eight months following fledging, and compare these to the trajectories
of 17 adults to assess differences and similarities in behavioral strategies through time.
Behavioral clustering algorithms (Expectation Maximization binary Clustering) were
combined with multinomial regression analyses to investigate changes in behavioral
mode probabilities over time, and how these may be influenced by variations in day
duration and in biophysical oceanographic conditions. We found that juveniles appeared
to quickly acquire the same large-scale
behavioral strategies as those employed
by adults, although generally more time was spent resting at night. Moreover, individuals
were able to detect and exploit specific oceanographic features in a manner
similar to that observed in adults. Together, the results of this study suggest that while
shortly after fledging juvenile wandering albatrosses are able to employ similar foraging
strategies to those observed in adults, additional skills need to be acquired during
the immature period before the efficiency of these behaviors matches that of adults.