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

Gynandromorphy like that in this cardinal occurs when a female egg cell develops with two nuclei—one with a Z and one with a W—and it's double fertilized by two Z-carrying sperm. The chimeric individual then develops with half of its body as a male ZZ and the other half as a female ZW. If you were to examine a cell from the bright red male side, it would have cells with ZZ chromosomes. If you looked at a cell from the left, it would have cells with ZW chromosomes. This phenomenon happens in birds, many insects, and crustaceans. (Be sure to check out this butterfly that's half male, half female with colors split down the middle and this half-orange, half-brown lobster.)