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Visual abilities in two raptors with different ecology

Potier, Simon; Bonadonna, Francesco; Kelber, Almut LU ; Martin, Graham R.; Isard, Pierre François; Dulaurent, Thomas and Duriez, Olivier (2016) In Journal of Experimental Biology 219(17). p.2639-2649
Abstract

Differences in visual capabilities are known to reflect differences in foraging behaviour even among closely related species. Among birds, the foraging of diurnal raptors is assumed to be guided mainly by vision but their foraging tactics include both scavenging upon immobile prey and the aerial pursuit of highly mobile prey. We studied how visual capabilities differ between two diurnal raptor species of similar size: Harris's hawks, Parabuteo unicinctus, which take mobile prey, and black kites, Milvus migrans, which are primarily carrion eaters. We measured visual acuity, foveal characteristics and visual fields in both species. Visual acuity was determined using a behavioural training technique; foveal characteristics were determined... (More)

Differences in visual capabilities are known to reflect differences in foraging behaviour even among closely related species. Among birds, the foraging of diurnal raptors is assumed to be guided mainly by vision but their foraging tactics include both scavenging upon immobile prey and the aerial pursuit of highly mobile prey. We studied how visual capabilities differ between two diurnal raptor species of similar size: Harris's hawks, Parabuteo unicinctus, which take mobile prey, and black kites, Milvus migrans, which are primarily carrion eaters. We measured visual acuity, foveal characteristics and visual fields in both species. Visual acuity was determined using a behavioural training technique; foveal characteristics were determined using ultra-high resolution spectraldomain optical coherence tomography (OCT); and visual field parameters were determined using an ophthalmoscopic reflex technique. We found that these two raptors differ in their visual capacities. Harris's hawks have a visual acuity slightly higher than that of black kites. Among the five Harris's hawks tested, individuals with higher estimated visual acuity made more horizontal head movements before making a decision. This may reflect an increase in the use of monocular vision. Harris's hawks have two foveas (one central and one temporal), while black kites have only one central fovea and a temporal area. Black kites have a wider visual field than Harris's hawks. This may facilitate the detection of conspecifics when they are scavenging. These differences in the visual capabilities of these two raptors may reflect differences in the perceptual demands of their foraging behaviours.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Black kite, Fovea, Harris's hawk, Raptor vision, Visual acuity, Visual field
in
Journal of Experimental Biology
volume
219
issue
17
pages
11 pages
publisher
The Company of Biologists Ltd
external identifiers
  • scopus:84988646786
  • wos:000384249800014
ISSN
0022-0949
DOI
10.1242/jeb.142083
language
English
LU publication?
yes
id
730fa44f-c228-4283-a601-198974524cd2
date added to LUP
2016-12-13 12:02:10
date last changed
2017-07-23 05:21:59
@article{730fa44f-c228-4283-a601-198974524cd2,
  abstract     = {<p>Differences in visual capabilities are known to reflect differences in foraging behaviour even among closely related species. Among birds, the foraging of diurnal raptors is assumed to be guided mainly by vision but their foraging tactics include both scavenging upon immobile prey and the aerial pursuit of highly mobile prey. We studied how visual capabilities differ between two diurnal raptor species of similar size: Harris's hawks, Parabuteo unicinctus, which take mobile prey, and black kites, Milvus migrans, which are primarily carrion eaters. We measured visual acuity, foveal characteristics and visual fields in both species. Visual acuity was determined using a behavioural training technique; foveal characteristics were determined using ultra-high resolution spectraldomain optical coherence tomography (OCT); and visual field parameters were determined using an ophthalmoscopic reflex technique. We found that these two raptors differ in their visual capacities. Harris's hawks have a visual acuity slightly higher than that of black kites. Among the five Harris's hawks tested, individuals with higher estimated visual acuity made more horizontal head movements before making a decision. This may reflect an increase in the use of monocular vision. Harris's hawks have two foveas (one central and one temporal), while black kites have only one central fovea and a temporal area. Black kites have a wider visual field than Harris's hawks. This may facilitate the detection of conspecifics when they are scavenging. These differences in the visual capabilities of these two raptors may reflect differences in the perceptual demands of their foraging behaviours.</p>},
  author       = {Potier, Simon and Bonadonna, Francesco and Kelber, Almut and Martin, Graham R. and Isard, Pierre François and Dulaurent, Thomas and Duriez, Olivier},
  issn         = {0022-0949},
  keyword      = {Black kite,Fovea,Harris's hawk,Raptor vision,Visual acuity,Visual field},
  language     = {eng},
  month        = {09},
  number       = {17},
  pages        = {2639--2649},
  publisher    = {The Company of Biologists Ltd},
  series       = {Journal of Experimental Biology},
  title        = {Visual abilities in two raptors with different ecology},
  url          = {http://dx.doi.org/10.1242/jeb.142083},
  volume       = {219},
  year         = {2016},
}