Rare 'half-male, half-female' cardinal photographed in Pennsylvania

Yep. Unless you check the gonads and the DNA on both sides, any explanation will be uncertain.

I note that birds use the WZ sex system, which is like the opposite of the mammalian XY sex system. Males are ZZ. Selective silencing of genes on the Z chromosome for dosage compensation could cause spacial variation across the body. We see something like this in the XY sex system with Barr bodies, leading to coloration differences such as those of the calico cat.

It's also possible to have a plain old male-male chimera, or a plain old mutation, with the cells in one part failing to produce the proper color.

Leucistic cardinals don't just look like female cardinals. https://lostpineslife.com/leucistic-northern-cardinal-winter...

I suspect it had to do with sex-associated traits were split down the middle. I'm only an amateur, but I can see that the right side has a male's long tail feathers while the left side does not. I imagine there are other details that would be apparent to an expert.

Came here to say something similar. It seems fairly obvious (to an amateur like me, I guess) that the lack of color on one side would simply be from a pigmentation issue. But the description of the event by the photographer as a "once-in-a-lifetime, one-in-a-million encounter" makes it seem like there's a very clear reason he narrowed out pigmentation.

Having grown up in an area without cardinals, I'm delighted to now live somewhere that has a few of them about in winter. There's a mated pair that keep pretty close together around our house, and they're a delight to watch together.

Having some activity in your back yard is definitely worth it, and there's so many people that don't have that because they (have to) live somewhere that's densely urbanized.

I had a very bland back yard (green ivies as walls, some other evergreen ground covering), but my girlfriend moved in two years ago and she's a gardener. We've got a diversity of plants now, the soil is alive again, and there's a popular bird feeder, regularly refilled, hanging on the shed now. We sometimes get a dozen birds flitting about there, who then get interrupted by a pair of magpies.

But, this whole neighbourhood I live in (very middle class, I'm at the outer edge) has been designed to allow for nature, with lots of semi-wild green spaces dotted around and lots of waterways.

We truly are blessed to live in a world with such wonders.

It’s much easier than in the film days. Great equipment can still give great results. I met this guy on a walk on the north shore of Massachusetts. with a 600mm lens. Much better reach than mine.

https://www.flickr.com/photos/bryanbatley/

As opposed to my setting up a GoPro on my moms feeder. Which is fun but not quite the same (she has a normal male cardinal)

https://youtu.be/BXMRen6lKEw

For one moment I thought this was about photography of naturism, which is a totally different thing.

I believe humans actually, I just stumbled upon this infographic today : https://static.scientificamerican.com/sciam/cache/file/164FE...

I don't have any sources for that but I have an anecdotal story.

While I was volunteering in a support group for transgender people, I once spoke to a woman who had a lot of complex issues with her hormone replacement therapy.

She was on a mix of medication that I had never seen before and I got worried that her health provider was prescribing an incorrect treatment.

This got me to ask questions I would never ask usually out of worry.

She told me that the reason that her medication was not the usual treatment is that she had a condition in which different parts of her bodies had different chromosomes. She told the exact name of the condition at the time but I did not write it down. I do remember the word "chimerism" being said during this conversation.

From experience, stories about weird conditions said by trans people are almost always true. She seemed very sincere about her struggles.

AFAIK gynandromorphism doesn't happen in mammals because sexual development is more centralized. Half of your body could have cells of a different sex but it wouldn't matter because organs responsible for sexual development will still effectively turn out one way. In other species each side of the body will develop quite differently because different cells is all it takes.

Tons of different human mosaics have been observed but it usually doesn't cause anything interesting.

Having different hair would imply chimerism - having two different sets of DNA. With mosaicism you start from one set of DNA but it may not duplicate the usual way.

Most if not all species with biological sex presentation. Binary sex characteristics are an abstraction and extend beyond a specific set of chromosomes (which also present more non-binary configurations). Most humans and other sexed animals bunch up on one side or the other but it’s still a convenience rather than an either/or fact.

You might find more luck with the term “intersex” or in more historical sources, hermaphroditism.

From the wiki for mosaic DNA:

> In rare cases, intersex conditions can be caused by mosaicism where some cells in the body have XX and others XY chromosomes (46, XX/XY).[12][13] In the fruit fly Drosophila melanogaster, where a fly possessing two X chromosomes is a female and a fly possessing a single X chromosome is a sterile male, a loss of an X chromosome early in embryonic development can result in sexual mosaics, or gynandromorphs.

> An example of this is one of the milder forms of Klinefelter syndrome, called 46,XY/47,XXY mosaic wherein some of the patient's cells contain XY chromosomes, and some contain XXY chromosomes.

So yes. Looks like it occurs in humans enough to be a big area of study for intersex understanding. There’s a lot of research on sex in this area, but it’s hard to dig through. (And a recommendation for the game “House of Fata Morgana” if you’d like a fictional telling of this history).

> Not much is known about the unusual phenomenon, but this sexual split has been reported among birds, reptiles, butterflies and crustaceans.

From an article linked in another comment: https://www.nytimes.com/2019/02/09/science/cardinal-sex-gend...

Try lobsters.

Just woke up, saw this title, rubbed my eyes to make sure I wasn't seeing things—and then realized what type of cardinal this was!

I'm glad I'm not the only one!

Came here to say this.

too funny

The Pope has some 'splainin to do.

I snorted. :)

I think the authors description of this being one-in-a-million must be pretty accurate then!

The article says it might be the same one.

Could it be the same cardinal at a different time of year?

I'm not sure whether or not they are migratory.

Props for choosing the better of the two Elder Scrolls wikis.

It's unlikely, since this resulted from an abnormality in early development, before the specimen developed an endoctrinal system.

N.b. that bisexual chmærism happens all the time, but tends to go unnoticed so long as both gonads belong to the same sex, which is typically the case, as they are organs located close together.

What triggers this is that both gonads belong to different strata of the chimæra, and that thus one develops into male gonads, and the other into female gonads.

One's entire body can belong to a female stratum in the chimæra, but so long as only the tissue that forms the gonads belongs to a male stratum, they will develop into testes, and influence the entire female stratum to also develop masculine characteristics, as male and female cells are not differently receptive to sex hormones.

This is not an endocrine disruption but a genetic condition.

endocrine disrupting chemicals cannot change sex.

It's ironic how the most insightful comments on this site get the most downvotes. As if endocrine disrupting chemicals in the enivronment are not a possible contributing factor, and the eventual downfall and extinction of most if not all species. [1]

[1] https://www.axios.com/falling-sperm-count-endocrine-disrupti...

The state bird of Pennsylvania is the Ruffed Grouse. The Cardinal is the state bird of a different Commonwealth: Virginia.

Merlin has no trouble with it, unsurprisingly.

Exactly, I wonder if it was their inspiration

Good to see some levity in some of these threads.