Birds perceive ‘warm’ colors differently from ‘cool’ ones. Duke Today, May 29, 2019. Birds may not have a word for maroon. Or burnt sienna. But show a zebra finch a sunset-colored object, and she’ll quickly decide whether it looks more “red” or “orange.” A new study shows that birds mentally sort the range of hues on the blue-green side of the spectrum into two categories too, but the line between them is fuzzier, perhaps because “either/or” thinking is less useful in this part of the spectrum, researchers say.