Dull-Colored Birds Don't See the World Like Colorful Birds Do
upstart writes in with an IRC submission for Runaway1956:
Dull-colored birds don't see the world like colorful birds do:
According to a new Duke University study, the ability to mentally categorize colors is not a universal avian attribute, and dull-colored birds may see the world in a completely different way than their colorful cousins.
[...] In a new study, appearing Oct. 26 in The American Naturalist, the team turned their attention to Bengalese finches, a species of brown, black and white birds that don't rely on colorful signals when choosing a mate. When presented with the same continuum of colors, Bengalese finches showed no evidence of a threshold between orange and red. Instead, they picked only disks that were on opposite sides of the continuum and differed a lot in hue. They seemed to be paying more attention to differences in brightness than the zebra finches.
"Brightness matters for all of these birds, but it really is what is driving the ability of the Bengalese finch to discriminate among colors, not hue," said Steve Nowicki, a Duke biology professor who is senior author on the study.
[...] These results show that vision depends on much more than the eyes. The colors that an animal sees depend on how important that color is for its everyday life.
"A two-species comparison is not much to hang an evolutionary story on," Nowicki said. Nonetheless, these two species are enough to point out flaws in previous assumptions.
[...] The authors hope that a more comprehensive study with several species will shed light on how the perception of color relates to the presence of colorful signals in birds. What these two species can say, however, is already a breakthrough.
Journal Reference:
Eleanor M. Caves, Patrick A. Green, Matthew N Zipple, Dhanya Bharath, Susan Peters, Sonke Johnsen, and Stephen Nowicki, Comparison of categorical color perception in two Estrildid finches, (DOI: 10.1086/712379)
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