An extremely fascinating and rare species of bird has been observed: a half-vermilion, half-dove-gray cardinal . The anomaly is called “ bilateral gynandromorphism ”: half of the animal's body is male and the other half is female. This condition would derive from an unbalanced distribution of sex chromosomes in the early stages of embryonic development.
Gynandromorphic individuals can have both male and female genitalia and are often sterile. Gynandromorphs are rare but not impossible to find. This phenomenon occurs in birds, many insects and crustaceans. They probably occur in many more species than we can imagine, but experts are unable to notice them in all specimens because not all of them present such clear-cut distinctions between the male animal and the female animal.
Cardinals are the best known sexually dimorphic birds in North America so the anomaly is immediately noticeable. So what makes these species so fascinating? Most animals with gynandromorphism are sterile , but this specimen may not be as the left side (where the ovary is in operation in birds) is female.
When viewed in profile it looks like a bird like many others, but if you look at it from the front you will see what nature is capable of.