Visual Adaptations in Predatory and Scavenging Diurnal Raptors
Department of Biology, Lund University, Sölvegatan 35, S-22362 Lund, Sweden
Diversity 2020, 12(10), 400; https://doi.org/10.3390/d12100400
Received: 1 September 2020 / Revised: 24 September 2020 / Accepted: 14 October 2020 / Published: 15 October 2020
(This article belongs to the Special Issue Ecology of Predation and Scavenging and the Interface)
Ecological diversity among diurnal birds of prey, or raptors, is highlighted regarding their sensory abilities. While raptors are believed to forage primarily using sight, the sensory demands of scavengers and predators differ, as reflected in their visual systems. Here, I have reviewed the visual specialisations of predatory and scavenging diurnal raptors, focusing on (1) the anatomy of the eye and (2) the use of vision in foraging. Predators have larger eyes than scavengers relative to their body mass, potentially highlighting the higher importance of vision in these species. Scavengers possess one centrally positioned fovea that allows for the detection of carrion at a distance. In addition to the central fovea, predators have a second, temporally positioned fovea that views the frontal visual field, possibly for prey capture. Spatial resolution does not differ between predators and scavengers. In contrast, the organisation of the visual fields reflects important divergences, with enhanced binocularity in predators opposed to an enlarged field of view in scavengers. Predators also have a larger blind spot above the head. The diversity of visual system specializations according to the foraging ecology displayed by these birds suggests a complex interplay between visual anatomy and ecology, often unrelatedly of phylogeny.