Four millennia of long-term individual foraging site fidelity in a highly migratory marine predator

Theory and field studies suggest that long-term individual foraging site fidelity (IFSF) can be an adaptation to density-driven competition, but confirming its mechanisms and prevalence in wild, long-lived migratory animals has been difficult. Using temporal stable isotope datasets, the authors test for long-term patterns in geographic foraging of the endangered short-tailed albatross (Phoebastria albatrus) across four millennia prior to their near-extinction. Isotopic analyses of archaeological bone collagen and historical feathers reveal that past sub-populations exhibited high degrees of long-term IFSF, repeatedly focusing on the same foraging areas for hundreds of generations—behavior not evident in today’s population. This provides the first large-scale evidence for deep antiquity of long-term IFSF and supports density-dependent drivers. As populations recover from overexploitation, a resurgence of geographic specialization could increase exposure to localized hazards, underscoring the need for enhanced conservation monitoring.