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 previous experiments, a team led by Duke postdoctoral researcher Eleanor Caves showed that female zebra finches presented with a continuum of orange to red colors will categorize these into two distinct groups with a clear threshold. These birds have brightly colored orange to red beaks, which may act as a signal of health when females are choosing their mate.
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. [...]
“First we showed that birds can see the rainbow,” said Steve Nowicki, Duke Biology professor and senior author on the paper. “Now we’re saying: actually, not all of them do!”
Dull-Colored Birds Don't See The World Like Bright Birds Do, By Marie Claire Chelini, Duke Today 10/30/2020.
Funding for this study was provided by the Duke University Office of the Provost.
CITATION: “Comparison of Categorical Color Perception in Two Estrildid Finches," Caves, E. M., Green, P.A., Zipple, M. N., Bharath, D., Peters, S., Johnsen, S., and Nowicki, S. The American Naturalist, Oct. 26, 2020. DOI: 10.1086/712379