Eye Size, Fovea, and Foraging Ecology in Accipitriform Raptors

TY - JOUR

T1 - Eye Size, Fovea, and Foraging Ecology in Accipitriform Raptors

AU - Potier, Simon

AU - Mitkus, Mindaugas

AU - Bonadonna, Francesco

AU - Duriez, Olivier

AU - Isard, Pierre François

AU - Dulaurent, Thomas

AU - Mentek, Marielle

AU - Kelber, Almut

PY - 2017

Y1 - 2017

N2 - 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.

AB - 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.

KW - Bird visual ecology

KW - Carrion eaters

KW - Eye size

KW - Foraging

KW - Fovea

KW - Predators

U2 - 10.1159/000479783

DO - 10.1159/000479783

M3 - Article

C2 - 29020667

AN - SCOPUS:85031402399

VL - 90

SP - 232

EP - 242

JO - Brain, Behavior and Evolution

JF - Brain, Behavior and Evolution

SN - 0006-8977

IS - 3

ER -