Talking about having a split personality. A recent story from Live Science reported on a half male/half female chimera cardinal that was discovered in Pennsylvania (pictured below). Not only are the bird’s feathers split (red feathers are found among male and tan among female cardinals), typically the brain is also split.
This type of a split sexuality is termed gynandromorph. According to the article, this anomaly has been observed in birds, crustaceans and butterflies. Female birds have both sex chromosomes (W and Z in birds) and males only carry one (Z). If a female egg has two nuclei, one could contain the W chromosome and the other the Z chromosome. If fertilized, the egg could develop with ZZ and ZW chromosomes resulting the development of a half-male and half-female bird.