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High resolution of colour vision, but low contrast sensitivity in a diurnal raptor

Potier, Simon LU ; Mitkus, Mindaugas LU and Kelber, Almut LU (2018) In Proceedings of the Royal Society B: Biological Sciences 285.
Abstract
Animals are thought to use achromatic signals to detect small (or distant) objects and chromatic signals for large (or nearby) objects. While the spatial resolution of the achromatic channel has been widely studied, the spatial resolution of the chromatic channel has rarely been estimated. Using an operant conditioning method, we determined (i) the achromatic contrast sensitivity function and (ii) the spatial resolution of the chromatic channel of a diurnal raptor, the Harris's hawk Parabuteo unicinctus The maximal spatial resolution for achromatic gratings was 62.3 c deg-1, but the contrast sensitivity was relatively low (10.8-12.7). The spatial resolution for isoluminant red-green gratings was 21.6 c deg-1-lower than that of the... (More)
Animals are thought to use achromatic signals to detect small (or distant) objects and chromatic signals for large (or nearby) objects. While the spatial resolution of the achromatic channel has been widely studied, the spatial resolution of the chromatic channel has rarely been estimated. Using an operant conditioning method, we determined (i) the achromatic contrast sensitivity function and (ii) the spatial resolution of the chromatic channel of a diurnal raptor, the Harris's hawk Parabuteo unicinctus The maximal spatial resolution for achromatic gratings was 62.3 c deg-1, but the contrast sensitivity was relatively low (10.8-12.7). The spatial resolution for isoluminant red-green gratings was 21.6 c deg-1-lower than that of the achromatic channel, but the highest found in the animal kingdom to date. Our study reveals that Harris's hawks have high spatial resolving power for both achromatic and chromatic vision, suggesting the importance of colour vision for foraging. By contrast, similar to other bird species, Harris's hawks have low contrast sensitivity possibly suggesting a trade-off with chromatic sensitivity. The result is interesting in the light of the recent finding that double cones-thought to mediate high-resolution vision in birds-are absent in the central fovea of raptors. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
colour vision, contrast sensitivity, foraging, raptors, spatial resolution
in
Proceedings of the Royal Society B: Biological Sciences
volume
285
pages
7 pages
publisher
Royal Society
external identifiers
  • scopus:85065548538
ISSN
1471-2954
DOI
10.1098/rspb.2018.1036
language
English
LU publication?
yes
id
21ebe5ee-81ec-49ed-969d-3e4b932daa83
date added to LUP
2019-03-12 09:49:08
date last changed
2019-10-15 07:00:12
@article{21ebe5ee-81ec-49ed-969d-3e4b932daa83,
  abstract     = {Animals are thought to use achromatic signals to detect small (or distant) objects and chromatic signals for large (or nearby) objects. While the spatial resolution of the achromatic channel has been widely studied, the spatial resolution of the chromatic channel has rarely been estimated. Using an operant conditioning method, we determined (i) the achromatic contrast sensitivity function and (ii) the spatial resolution of the chromatic channel of a diurnal raptor, the Harris's hawk Parabuteo unicinctus The maximal spatial resolution for achromatic gratings was 62.3 c deg-1, but the contrast sensitivity was relatively low (10.8-12.7). The spatial resolution for isoluminant red-green gratings was 21.6 c deg-1-lower than that of the achromatic channel, but the highest found in the animal kingdom to date. Our study reveals that Harris's hawks have high spatial resolving power for both achromatic and chromatic vision, suggesting the importance of colour vision for foraging. By contrast, similar to other bird species, Harris's hawks have low contrast sensitivity possibly suggesting a trade-off with chromatic sensitivity. The result is interesting in the light of the recent finding that double cones-thought to mediate high-resolution vision in birds-are absent in the central fovea of raptors.},
  articleno    = {20181036},
  author       = {Potier, Simon and Mitkus, Mindaugas and Kelber, Almut},
  issn         = {1471-2954},
  keyword      = {colour vision,contrast sensitivity,foraging,raptors,spatial resolution},
  language     = {eng},
  month        = {08},
  pages        = {7},
  publisher    = {Royal Society},
  series       = {Proceedings of the Royal Society B: Biological Sciences},
  title        = {High resolution of colour vision, but low contrast sensitivity in a diurnal raptor},
  url          = {http://dx.doi.org/10.1098/rspb.2018.1036},
  volume       = {285},
  year         = {2018},
}