Eye Size, Fovea, and Foraging Ecology in Accipitriform Raptors

Research output: Contribution to journalArticle


Birds with larger eyes are predicted to have higher spatial resolution because of their larger retinal image. Raptors are well known for their acute vision, mediated by their deep central fovea. Because foraging strategies may demand specific visual adaptations, eye size and fovea may differ between species with different foraging ecology. We tested whether predators (actively hunting mobile prey) and carrion eaters (eating dead prey) from the order Accipitriformes differ in eye size, foveal depth, and retinal thickness using spectral domain optical coherence tomography and comparative phylogenetic methods. We found that (1) all studied predators (except one) had a central and a temporal fovea, but all carrion eaters had only the central fovea; (2) eye size scaled with body mass both in predators and carrion eaters; (3) predators had larger eyes relative to body mass and a thicker retina at the edge of the fovea than carrion eaters, but there was no difference in the depth of the central fovea between the groups. Finally, we found that (4) larger eyes generally had a deeper central fovea. These results suggest that the visual system of raptors within the order Accipitriformes may be highly adapted to the foraging strategy, except for the foveal depth, which seems mostly dependent upon the eye size.


  • Simon Potier
  • Mindaugas Mitkus
  • Francesco Bonadonna
  • Olivier Duriez
  • Pierre François Isard
  • Thomas Dulaurent
  • Marielle Mentek
  • Almut Kelber
External organisations
  • University of Montpellier
  • Paul Valéry University of Montpellier
  • Centre Hospitalier Vétérinaire Saint-Martin
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Ecology


  • Bird visual ecology, Carrion eaters, Eye size, Foraging, Fovea, Predators
Original languageEnglish
Pages (from-to)232-242
JournalBrain, Behavior and Evolution
Issue number3
Early online date2017 Oct 12
Publication statusPublished - 2017
Publication categoryResearch