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.

In fact, they weren't sure they saw it correctly until it came in closer. "Never did we ever think we would see something like this in all the years we've been feeding," Shirley Caldwell says. 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.