At-sea distribution and scale-dependent foraging behaviour of petrels and albatrosses: a comparative study
Article first published online: 27 NOV 2006
Journal of Animal Ecology
Volume 76, Issue 1, pages 9–19, January 2007
How to Cite
PINAUD, D. and WEIMERSKIRCH, H. (2007), At-sea distribution and scale-dependent foraging behaviour of petrels and albatrosses: a comparative study. Journal of Animal Ecology, 76: 9–19. doi: 10.1111/j.1365-2656.2006.01186.x
- Issue published online: 27 NOV 2006
- Article first published online: 27 NOV 2006
- Received 8 August 2006; accepted 28 September 2006
- area-restricted search;
- First-Passage Time;
- foraging distribution;
- spatial scale
- 1In order to study and predict population distribution, it is crucial to identify and understand factors affecting individual movement decisions at different scales. Movements of foraging animals should be adjusted to the hierarchical spatial distribution of resources in the environment and this scale-dependent response to environmental heterogeneity should differ according to the forager's characteristics and exploited habitats.
- 2Using First-Passage Time analysis, we studied scales of search effort and habitat used by individuals of seven sympatric Indian Ocean Procellariiform species fitted with satellite transmitters. We characterized their search effort distribution and examined whether species differ in scale-dependent adjustments of their movements according to the marine environment exploited.
- 3All species and almost all individuals (91% of 122 individuals) exhibited an Area-Restricted Search (ARS) during foraging. At a regional scale (1000s km), foraging ranges showed a large spatial overlap between species. At a smaller scale (100s km, at which an increase in search effort occurred), a segregation in environmental characteristics of ARS zones (where search effort is high) was found between species.
- 4Spatial scales at which individuals increased their search effort differed between species and also between exploited habitats, indicating a similar movement adjustment for predators foraging in the same habitat. ARS zones of the two populations of wandering albatross Diomedea exulans (Crozet and Kerguelen) were similar in their adjustments (i.e. same ARS scale) as well as in their environmental characteristics. These two populations showed a weak spatial overlap in their foraging distribution, with males foraging in more southerly waters than females in both populations.
- 5This study demonstrates that predators of several species adjust their foraging behaviour to the heterogeneous environment and these scale-dependent movement adjustments depend on both forager and environment characteristics.