Home range requirements in Bonelli’s eagle (Aquila fasciata): prey abundance or trophic stability?

MARTÍNEZ-MIRANZO, BEATRIZ; AGUIRRE, JOSÉ I.; BANDA, EVA

EUROPEAN JOURNAL OF WILDLIFE RESEARCH

SPRINGER

Año: 2019 p. 1 - 8

1612-4642

Prey abundance is one of the limiting factors for establishment a home range. In particular, biomass abundance could act as a keyelement for generalist top predators, with wide prey type spectrum, for establishing their home ranges. We studied if biomassabundance may act as a limiting factor for the establishment of home range in a generalist top predator, Bonelli?s eagle (Aquilafasciata). We used GPS satellite data on breeding individuals over a 10-year period to deepen into home range behaviour. Toquantify biomass abundance, we performed surveys at different periods of the year cycle for potential prey inside the homeranges and outside them.We checked if differences in biomass were identified between home ranges and potential adjacent areas.Also, annual and seasonal variation in biomass abundance may be recorded. Variations in biomass abundance among home rangewere detected but no annual or seasonal variation within home range was identified. Differences in biomass abundance wereidentified between each of the home range and their potential adjacent areas. Although biomass abundance is lower inside thehome range, it remains stable throughout the year while strong fluctuations in biomass abundance were detected outside them.Our results show that Bonelli?s eagle may establish their home range based on permanent biomass stability (Trophic StabilityHypothesis) rather than great seasonal but unpredictable abundances. This approach may have strong implications for managementconservation programs of territorial top generalist predators.