Knowledge of the factors influencing foraging efficiency in top predators can help to
understand their foraging behaviour, and to predict the effects of environmental changes on
their population. Previous research on seabird foraging mainly focussed on search time, but
information on factors influencing capture success and profitability of a prey event is not
widely available. In the present study, bird-borne cameras were used to study the factors
influencing prey capture success, chase time, handling time and prey profitability in
Australasian gannets (Morus serrator). The results of this study suggest a lower capture success
when foraging solitary. Further on, foraging in multispecies groups increased chase time and
high prey densities increased chase and handling time. Only the biggest prey was found to
increase handling time. Profitability was mainly influenced by the targeted prey type, and
negative influences on profitability were caused by a high prey density and by foraging in
multispecies groups. Our findings suggest that foraging efficiency is mainly influenced by
factors associated to the environment, and for this reason changes in the environment can be
expected to have influences on the Australasian gannet population.
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