JOIN
OUR EMAIL LIST!
Screengrab/Twitter:@amcafee

To the untrained eye a strangely colored bird might have just looked like a beautiful anomaly, but the two amateur birdwatchers who spotted it knew they were witnessing something special.


For the past 25 years Jeffrey and Shirley Caldwell have been feeding and watching the birds that find their way into the backyard of their Erie, Pennsylvania home.

At the beginning of January though the couple began spotting an unusual cardinal that was unlike any bird they had ever seen before.

The bird's half red, half light feathers were split right down the middle.

It's a genetic anomaly known as a bilateral gynandromorph. The phenomenon is so rare that Jeffrey and Shirley couldn't be sure of what they were seeing until the cardinal began flying closer to their house.



"Never did we ever think we would see something like this in all the years we've been feeding," says Shirley.

Once the bird got close enough Shirley was ready to grab some footage of the wonderful creature.


Put simply gynandromorphs are half male and half female.

"This remarkable bird is a genuine male/female chimera," Daniel Hooper, a postdoctoral fellow at the Cornell Lab of Ornithology, wrote in an email to National Geographic.

The trait known as sexual dimorphism also occurs in insects and crustaceans like butterflies and lobsters. In birds it is thought to occur across all species, but in cardinals it is especially noticeable.

Ornithologists refer to them as "half-siders"

"Cardinals are one of the most well-known sexually dimorphic birds in North America," according to Hooper.

"Their bright red plumage in males is iconic—so people easily notice when they look different."

What makes these "half-siders" so different?

Hooper tells NatGeo that most female birds carry one copy of each sex chromosome, called Z and W in birds, whereas males have two copies of the Z chromosome.

It's the opposite in humans where most males have X and Y chromosomes and most females have two X chromosomes.

In birds, sex is determined by the female's eggs which typically carry only one Z or W chromosome, which is then fertalized by the male's Z chromosome sperm.

In dimorphic eggs however the cell develops two nuclei carrying Z and W chromosomes which are then both fertilized by by two Z chromosome sperm.

The result is a chimera who develops a half male ZZ and half female ZW body.

Gynandromorphs like the Caldwell's cardinal aren't unheard of, but they are rare enough that it is usually a big deal when they are spotted.


Carolyn Carpenter Tamburrino/Facebook


Amy Cowell/Facebook


Coury James/Facebook


Terry L. Sage/Facebook


Warren Butchy Kolbenheyer/Facebook


The Caldwell's cardinal however may be even more rare.

In most cases gynandromorphs are born infertile and unable to reproduce, but in the case of the Caldwell's bird the left side of its body is female.

While female birds have ovaries on both sides only the left side ovaries are functional. So the Caldwell's bird may be able to reproduce.

And the Caldwells say their cardinal may even have a mate.

Shirley says she often spots her gynandromorph in the company of a male bird.

"We're happy it's not lonely," Shirley says.

It's hard to know for sure if the cardinal will be able to reproduce, but Shirley is certainly hoping so.

"Who knows, maybe we will be lucky enough to see a family in summer!"
Image by Mary Pahlke from Pixabay

There are few things more satisfying than a crisp $20 bill. Well, maybe a crisp $100 bill.

But twenty big ones can get you pretty far nonetheless.

Whether it's tucked firmly in a birthday card, passing from hand to hand after a knee-jerk sports bet, or going toward a useful tool, the old twenty dollar bill has been used for countless purposes.


Keep reading... Show less
Image by Jan Vašek from Pixabay

I realize that school safety has been severely compromised and has been under dire scrutiny over the past decade and of course, it should be. And when I was a student, my safety was one of my greatest priorities but, some implemented rules under the guise of "safety" were and are... just plain ludicrous. Like who thinks up some of these ideas?

Redditor u/Animeking1108 wanted to discuss how the education system has ideas that sometimes are just more a pain in the butt than a daily enhancement... What was the dumbest rule your school enforced?
Keep reading... Show less
Image by Angelo Esslinger from Pixabay

One of the golden rules of life? Doctors are merely human. They don't know everything and they make mistakes. That is why you always want to get another opinion. Things are constantly missed. That doesn't mean docs don't know what they're doing, they just aren't infallible. So make sure to ask questions, lots of them.

Redditor u/Gorgon_the_Dragon wanted to hear from doctors about why it is imperative we always get second and maybe third opinions by asking... Doctors of Reddit, what was the worse thing you've seen for a patient that another Doctor overlooked?
Keep reading... Show less
Image by nonbirinonko from Pixabay

When we think about learning history, our first thought is usually sitting in our high school history class (or AP World History class if you're a nerd like me) being bored out of our minds. Unless again, you're a huge freaking nerd like me. But I think we all have the memory of the moment where we realized learning about history was kinda cool. And they usually start from one weird fact.

Here are a few examples of turning points in learning about history, straight from the keyboards of the people at AskReddit.

U/Tynoa2 asked: What's your favourite historical fact?


Keep reading... Show less