Site fidelity of male Galápagos sea lions: a lifetime perspective
Knowledge about the distribution of resources can lead to the development of spatial preferences and long-term site fidelity. Individuals are expected to choose sites that best suit their needs. However, dominant individuals restrict movements of less competitive ones. Accordingly, one may expect spatial preferences to differ with regard to individual characteristics and to change over time. We investigated lifetime changes of site fidelity patterns with regard to reproductive success in male Galápagos sea lions (Zalophus wollebaeki). Showing a high degree of natal philopatry in the first 2 years of life, non-territorial males pass through a stage of fidelity to their natal colony where they develop preferences for areas outside prime breeding areas. Variation in the degree of spatial preferences was not associated with age or size, characteristics linked to an individual’s dominance status. For non-territorial males, roaming proved to be an adequate strategy to gain reproductive success. Only the most competitive males established territories in areas preferentially visited by females. They had a high probability to return to breeding areas where they successfully reproduced in previous seasons. Overall, the results reveal lifetime changes in site fidelity with regard to male status. The degree of site fidelity observed within the colony suggests familiarity and thus a high degree of tolerance among individuals using the same areas. This seems to facilitate attendance in the colony and thus the possibility to prospect for oestrus females.
KeywordsPhilopatry Life history Intra-sexual competition Reproductive strategy Age-related dominance
This study was funded by the VW-Stiftung, Friends of the Galapagos Switzerland, German Research Foundation (TR 105/18, TR 105/18-2), German Academic Exchange Service and the Ethological Society. We are grateful for the permission and close collaboration of the Galápagos National Park Service as well as the logistical support of the Charles Darwin Research Station. We thank J.B.W. Wolf, B. Müller, and U. Pörschmann who ran the project in previous years. E. Hippauf and P. Viehoever helped with DNA analysis. This study could not have been done without the enduring field assistance of many helpers.
The study presented here complies with the laws of Ecuador and was licensed by the Galápagos National Park Service.
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