Rare half-male, half-female cardinal spotted in Pennsylvania
Jeffrey and Shirley Caldwell have been attracting birds for 25 years with carefully tended backyard feeders. But the lifelong Erie, Pennsylvania, residents have never seen a creature so wondrous as the half-vermillion, half-taupe cardinal—its colors split right down the middle—that first showed up a few weeks ago in the dawn redwood tree 10 yards from their home.
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The anomaly is known as a bilateral gynandromorph. In plain language: Half its body is male and the other half is female. “This remarkable bird is a genuine male/female chimera,” says Daniel Hooper, a postdoctoral fellow at the Cornell Lab of Ornithology, in an email.
Gynandromorphs, known as “half-siders” among ornithologists, are uncommon but not unheard of. They likely occur across all species of birds, Hooper says, but we’re only likely to notice them in species where the adult males and females look distinct from each other, a trait known as sexual dimorphism. “Cardinals are one of the most well-known sexually dimorphic birds in North America—their bright red plumage in males is iconic—so people easily notice when they look different,” Hooper says.
