'Split-Sex' Cardinal: the Loneliest Bird

When it comes to gender, birds really can have their cake and eat it too, but only at the cost of a very lonely life. That's at least according to new research on a "split-sex" cardinal discovered nearly six years ago - a bird that boasts both genders clearly on each side of its body, as represented by its stunning half-and-half plumage.

The phenomenon, called gynandromorphism, has long been known to exist in insects, crustaceans, and birds. It essentially is a rare and remarkable mutation that results in an organism being of both sexes. However, it is not a hermaphrodite or "intersex" (characterized by both or ambiguous genitalia). Instead, the sexes and their associated cells are evenly divided among the organism, resulting in parts of the body and even the brain being entirely female or male.

As in the case of this cardinal, this is best seen in bilateral gynandromorphs, in which the genders are evenly split right down the middle, causing two exact halves of the same creature to be of the opposite sex. As seen in a stunning butterfly exhibit at London's Natural History Museum back in 2011, this also means that genital development is evenly divided, resulting in an infertile fusion of halves.

According to field study observations just recently published in The Wilson Journal of Ornithology, researchers Robet Motz and Brian Peer at Western Illinois University had the rare opportunity to find and follow the bilateral cardinal as it lived out its life for two years. Forty days of observation were recorded, and the researchers reached various conclusions about the life of a gynandromorph.

They found, for the most part, this cardinal was quiet and lonely. Predictably, the cardinal never found a mate, and it was unclear if it even had any desire to reproduce. The researchers never even heard it sing, which suggests that it had no drive or reason to do so.

However, life isn't too bad for such a cardinal. The researchers observed that it also wasn't "subjected to any unusual agonistic behaviors from other cardinals," especially males, who often bicker among one another for food and space.

And while that tells us a little more about this unusual and natural phenomenon, there is still a lot to learn. The researchers noted that this cardinal's plumage is the complete opposite coloration of another gynandromorph sighted in 1969 - a bird with bright red on the right, and pale female feathers on the left.

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