Long‐term individual foraging site fidelity—why some gannets don't change their spots

• DOI: 10.1890/14-1300.1
• Publication Date: 2015-11-19T21:46:07Z
• Authors: Ewan D. Wakefield; Ian R. Cleasby; Stuart Bearhop; Thomas W. Bodey; Rachel D. Davies; Peter I. Miller; Jason Newton; Stephen C. Votier; Keith C. Hamer
• Keywords: Optimal foraging theory

Many established models of animal foraging assume that individuals are ecologically equivalent. However, it is increasingly recognized populations may comprise who differ consistently in their diets and behaviors. For example, recent studies have shown individual site fidelity (IFSF, when forage only a small part population's home range) occurs some colonial breeders. Short‐term IFSF could result from animals using win–stay, lose–shift strategy. Alternatively, be consequence specialization. Pelagic seabirds central‐place foragers, classically assumed to use flexible strategies target widely dispersed, spatiotemporally patchy prey. tracking has many seabirds, although not known whether this persists across years. To test for long‐term examine alternative hypotheses concerning its cause, we repeatedly tracked 55 Northern Gannets ( Morus bassanus ) large colony the North Sea within three successive breeding seasons. foraged neritic waters, predictably structured by tidal mixing thermal stratification, but subject stochastic, wind‐induced overturning. Both years, coarse mesoscale (tens kilometers) was significant absolute, birds departed individually consistent directions. Carbon stable isotope ratios gannet blood tissues were repeatable years nitrogen also suggesting dietary Individuals habitat with respect relative sea surface temperature dive metrics, yet none these factors accounted IFSF. Moreover, at scale weeks, did decay over time magnitude similar primarily foraging. Rather, hypothesize familiarity, accrued early life, causes canalizing subsequent decisions. Evidence other suggests common far‐reaching consequences our attempts understand conserve rapidly changing environment.