Rare Half-Male, Half-Female Cardinal Spotted In Pennsylvania

Bird is what's known as a bilateral gynandromorph, with male and female traits. This happens when female egg with two nuclei is 'double fertilized' by two sperm. The amazing male-female chimera was spotted in a Pennsylvania backyard. Male cardinals have bright red coloring; females have a much duller appearance.

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. (Further reading: This yellow cardinal is one-in-a-million.) (This gynandromorphic cardinal has been seen eating in the backyard of bird-lovers Shirley and Jeffrey Caldwell. Shirley snapped a photo of the rare bird through her kitchen window as it perched on a tree at the end of her yard.)