We all need more sunshine in our lives, those bright spots of color and glowing warmth that make us smile, lighten our burdens and remind us that there are always good things to enjoy. That “sunshine” might be different for everyone, and for birders, it might be a new yard bird, a visit from a favorite species or something really unusual. In rare cases, one bird could be all three, such as a xanthochroistic bird.
Xanthocroism is unusually strong yellow coloration in a bird’s plumage, often in place of more typical red, green or orange coloration but without affecting other colors or markings. Typically caused by a genetic abnormality that removes dark pigments from a bird’s plumage and allows yellow coloration to be bolder, limited xanthochroism can also be caused by a change in diet or the prevalence of different foods that affect plumage pigmentation.
Unlike albinism, which can create a creamy yellow pigmentation across all of a bird’s plumage, xanthochroism is confined to the areas of a bird’s feathers that would normally have the red, green or orange coloration, and other colors are not altered in any way. A xanthochroistic bird is usually very bright yellow wherever it would naturally have red, green or orange plumage, and its eyes, bill, legs, feet and other plumage colors remain unchanged.
Birds recorded with some degree of xanthochroism in their
populations include rose-breasted grosbeaks, Cape May warblers, red-bellied woodpeckers, northern cardinals, great spotted woodpeckers, evening grosbeaks, keas, crimson-breasted shrikes, purple finches and Cassin’s finches. House finches also often appear to be xanthochroistic, though their color variations are more likely dietary in origin and the color may not be as striking.
In January and February 2018, a rare yellow northern cardinal was spotted in Alabama, where it happily visited yards and delighted local birders. In 2009, a rose-breasted grosbeak with a brilliant yellow chest was reported in Ontario, and I myself witnessed a stunningly yellow Cassin’s finch in my yard in Utah, also in 2009. Reports of these dramatically different birds are obviously rare but regular, and each one is a remarkable sighting, and a brilliant ray of sunshine for all who see these birds.
Many thanks to Jeremy Black Photography for permission to share the xanthochroistic cardinal!