Full article: http://www.whitewolfpack.com/2012/09/half-male-half-female-cardinal-photos.html
(Edited for spelling). Male cardinals are bright red while females are a dull brownish color to provide camouflage. This particular bird sports the coloration of both birds and is literally split down the middle.
But in birds, unlike flies (or humans), the females are heterogametic: i.e., their sex chromosomes are different (the females are called ZW; and the males are ZZ). I’m not sure whether chromosome loss is involved in the production of this cardinal, or how that loss affects sex determination in birds (in humans, for example, unlike flies, the Y chromosome is important, so XO individuals are not phenotypic males but largely phenotypic females). An article at Live Science on a similar gynandromorph cardinal in Texas offers the following theory, based on the observation that in gynandromorph chickens the female side is the normal ZW and the male side the normal ZZ:
It’s not known exactly how gynandromorphy happens in birds, Arnold said. The predominant theory is that an error occurs in the formation of an egg, which normally carries one chromosome to unite with the single chromosome carried by the sperm. But if an egg accidentally ends up with two chromosomes — a Z and a W — and if this aberrant egg is fertilized by two Z-carrying sperm, the bird that results will have some ZZ cells and some ZW cells, he explained.
That seems unlikely to me because it requires the concatenation of two rare events: an egg carrying two sex chromosomes instead of one (but the normal half complement of autosomes), uniting not with one sperm but with two." (SOURCE)
(Edited for spelling). Male cardinals are bright red while females are a dull brownish color to provide camouflage. This particular bird sports the coloration of both birds and is literally split down the middle.
But in birds, unlike flies (or humans), the females are heterogametic: i.e., their sex chromosomes are different (the females are called ZW; and the males are ZZ). I’m not sure whether chromosome loss is involved in the production of this cardinal, or how that loss affects sex determination in birds (in humans, for example, unlike flies, the Y chromosome is important, so XO individuals are not phenotypic males but largely phenotypic females). An article at Live Science on a similar gynandromorph cardinal in Texas offers the following theory, based on the observation that in gynandromorph chickens the female side is the normal ZW and the male side the normal ZZ:
It’s not known exactly how gynandromorphy happens in birds, Arnold said. The predominant theory is that an error occurs in the formation of an egg, which normally carries one chromosome to unite with the single chromosome carried by the sperm. But if an egg accidentally ends up with two chromosomes — a Z and a W — and if this aberrant egg is fertilized by two Z-carrying sperm, the bird that results will have some ZZ cells and some ZW cells, he explained.
That seems unlikely to me because it requires the concatenation of two rare events: an egg carrying two sex chromosomes instead of one (but the normal half complement of autosomes), uniting not with one sperm but with two." (SOURCE)
