Foraging plasticity of breeding Northern Rockhopper Penguins, Eudyptes moseleyi, in response to changing energy requirements
KAUST DepartmentBiological and Environmental Sciences and Engineering (BESE) Division
Red Sea Research Center (RSRC)
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AbstractDuring the breeding season, seabirds must balance the changing demands of self- and off-spring provisioning with the constraints imposed by central-place foraging. Recently, it was shown that Northern Rockhopper Penguins at Tristan da Cunha in the South Atlantic Ocean switch diet from lower to higher trophic level prey throughout their breeding cycle. Here, we investigated if this switch is reflected in their foraging behaviour, using time-depth recorders to study the diving behaviour of 27 guard and 10 crèche birds during the breeding season 2010 at Tristan da Cunha and obtaining complementary stomach contents of 20 birds. While no significant effects of breeding stage were detected on any foraging trip or dive parameters, stage/prey had a significant effect on feeding dive parameters, with dive duration, bottom time, and maximum depth explaining the majority of the dissimilarity amongst categories. We verified the previously shown dietary shift from zooplankton and cephalopods during the guard stage to a higher-energy fish-based diet during the crèche stage, which was reflected in a change in dive behaviour from shorter, shallower to longer, deeper dives. This prey switching behaviour may reflect preferential selection to account for the increased physiological needs of chicks or simply mirror changes in local prey abundance. Nonetheless, we show that Northern Rockhopper Penguins demonstrate behavioural plasticity as a response to their changing energy requirements, which is a critical trait when living in a spatio-temporally heterogeneous environment. This ability is likely to be particularly important under extrinsic constraints such as long-term environmental change.
CitationBooth JM, Steinfurth A, Fusi M, Cuthbert RJ, McQuaid CD (2018) Foraging plasticity of breeding Northern Rockhopper Penguins, Eudyptes moseleyi, in response to changing energy requirements. Polar Biology. Available: http://dx.doi.org/10.1007/s00300-018-2321-6.
SponsorsThis work was carried out under the auspices of the Flagship Species Fund of the Department of Environment, Food and Rural Affairs (DEFRA) and Fauna & Flora International with funding from DEFRA, the Royal Society for the Protection of Birds (RSPB) and other donors under Project FSF-Defra- 10-48. The Department of Environmental Affairs through the South African National Antarctic Programme and the Tristan da Cunha conservation department provided logistical support. Thanks to T. Glass, J. Repetto, G. Swain, C. Repetto, M. Green and K. Green of the Tristan Conservation Department for their support in the field. M. Connan and anonymous reviewers provided helpful comments on an earlier version of this manuscript. This work is based upon research supported by the South African Research Chairs Initiative of the Department of Science and Technology and the National Research Foundation. Funding was provided by SARCHI (Grant Number 64801).