title: Return customers: foraging site fidelity and the effect of environmental variability in wide-ranging antarctic fur seals.
abstract: Strategies employed by wide-ranging foraging animals involve consideration of habitat quality and predictability and should maximise net energy gain. Fidelity to foraging sites is common in areas of high resource availability or where predictable changes in resource availability occur. However, if resource availability is heterogeneous or unpredictable, as it often is in marine environments, then habitat familiarity may also present ecological benefits to individuals. We examined the winter foraging distribution of female Antarctic fur seals, Arctocephalus gazelle, over four years to assess the degree of foraging site fidelity at two scales; within and between years. On average, between-year fidelity was strong, with most individuals utilising more than half of their annual foraging home range over multiple years. However, fidelity was a bimodal strategy among individuals, with five out of eight animals recording between-year overlap values of greater than 50%, while three animals recorded values of less than 5%. High long-term variance in sea surface temperature, a potential proxy for elevated long-term productivity and prey availability, typified areas of overlap. Within-year foraging site fidelity was weak, indicating that successive trips over the winter target different geographic areas. We suggest that over a season, changes in prey availability are predictable enough for individuals to shift foraging area in response, with limited associated energetic costs. Conversely, over multiple years, the availability of prey resources is less spatially and temporally predictable, increasing the potential costs of shifting foraging area and favouring long-term site fidelity. In a dynamic and patchy environment, multi-year foraging site fidelity may confer a long-term energetic advantage to the individual. Such behaviours that operate at the individual level have evolutionary and ecological implications and are potential drivers of niche specialization and modifiers of intra-specific competition.
authors: Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia.
authors: Benjamin
authors: B
authors: Arthur
authors: Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia.
authors: Mark
authors: M
authors: Hindell
authors: Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa.
authors: Marthan
authors: M
authors: Bester
authors: British Antarctic Survey, Cambridge, United Kingdom.
authors: Phil
authors: P
authors: Trathan
authors: Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia.
authors: Ian
authors: I
authors: Jonsen
authors: British Antarctic Survey, Cambridge, United Kingdom.
authors: Iain
authors: I
authors: Staniland
authors: Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa.
authors: W Chris
authors: WC
authors: Oosthuizen
authors: Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa.
authors: Mia
authors: M
authors: Wege
authors: Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia.
authors: Mary-Anne
authors: MA
authors: Lea
mesh_terms: D000818:Animals; D000864:Antarctic Regions; D001522:Behavior, Animal; D017753:Ecosystem; D005260:Female; D046069:Fur Seals / Q000502:physiology*; D006702:Homing Behavior; D012621:Seasons