The dynamic trophic niche of an island bird of prey

Ecology and Evolution
Ulises BalzaAndrea Raya Rey

Abstract

Optimal foraging theory predicts an inverse relationship between the availability of preferred prey and niche width in animals. Moreover, when individuals within a population have identical prey preferences and preferred prey is scarce, a nested pattern of trophic niche is expected if opportunistic and selective individuals can be identified. Here, we examined intraspecific variation in the trophic niche of a resident population of striated caracara (Phalcoboenus australis) on Isla de los Estados (Staten Island), Argentina, using pellet and stable isotope analyses. While this raptor specializes on seabird prey, we assessed this population's potential to forage on terrestrial prey, especially invasive herbivores as carrion, when seabirds are less accessible. We found that the isotopic niche of this species varies with season, age, breeding status, and, to a lesser extent, year. Our results were in general consistent with classic predictions of the optimal foraging theory, but we also explore other possible explanations for the observed pattern. Isotopic niche was broader for groups identified a priori as opportunistic (i.e., nonbreeding adults during the breeding season and the whole population during the nonbreeding season) tha...Continue Reading

Associated Datasets

Sep 4, 2020·Andrea Raya-ReyUlises Balza

References

Nov 22, 2008·The Journal of Animal Ecology·Joseph K BumpJohn A Vucetich
Aug 1, 1997·Trends in Ecology & Evolution·G Perry, E R Pianka
Mar 16, 2011·The Journal of Animal Ecology·Andrew L JacksonStuart Bearhop
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Jul 22, 2011·Ecological Applications : a Publication of the Ecological Society of America·Alexander L Bond, Antony W Diamond
Feb 12, 2015·Oecologia·Seth D NewsomeStanley D Gehrt
Dec 6, 2017·Nature Ecology & Evolution·Simone Des RochesEric P Palkovacs
Apr 7, 2020·Nature Ecology & Evolution·Simon DucatezLouis Lefebvre
Jun 20, 2020·The American Naturalist·Quinn M R WebberEric Vander Wal

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