Now appearing at the bird feeder: a gynandromorph

Oh, for sure it’s not a raccoon climbing a building, but a cardinal is currently at the top of the list of animals that divert the nation’s attention from less important things.


Shirley Caldwell of Erie, Pa., spotted it in her backyard the other day and now bird watchers can’t get enough of it.

Half male. Half female. Percentages may vary.

It’s known as a a gynandromorph, NBC News says.

It was easy to spot because male cardinals have bright red coloring; females have the less spectacular golden hue.

National Geographic explains the science of the Z and W chromosomes in birds.

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.

This cardinal may be able to reproduce. Caldwell says its apparent mate is a male cardinal in her backyard.

  • As this phenomenon illustrates, gender is not so sharply defined in nature as religious authoritarians would have us believe.

  • Rob

    Cool post. Does this condition have any effect on health or longevity?

    • kevins

      No, but it makes dating choices hell.

      • Gary F

        and since the whole world is its bathroom, that issue is a non factor too.

      • Hardly – It actually DOUBLES the chances for a date on Friday night.

  • ec99

    WOW! A beautiful bird! I have over a dozen male and female cardinals at my feeder, but nothing like that.