It is an exceptional bird: a cardinal half male, half female

The bird that Shirley and Jeffrey Caldwell have seen outside their home in the past few days is the strangest bird he has ever seen.

The cardinal has on the left side the brown shadow of the females; to the right, the distinctive scarlet of the males.

Researchers believe that the cardinal who frequents Caldwell bird feeders in Erie, Pennsylvania, is a strange bilateral gynandromorph, half male and half female. This atypical phenomenon is poorly known, but this badual division has been reported in birds, reptiles, butterflies and crustaceans.

No one can be sure that the bird is a gynandromorph without first badyzing its genes with blood samples or by means of an autopsy, but division in the middle of the plumage is characteristic of these extraordinary cases, according to Daniel Hooper, a Evolutionary biologist at Cornell University's Ornithology Laboratory.

Hooper mentioned that in theory, ginandromorphs could be created through the fusion of two developing embryos separately fertilized.

It is also possible for a female to produce an egg containing both copies of her bad chromosomes, Z and W, and then to fertilize two spermatozoa, each with a Z chromosome (although bad chromosomes in humans have the same effect). Label XX for chromosomes). women and XY in men, females are ZW and males, ZZ). Scientists do not really know how an egg of this type can produce a chick that has both ZW and ZZ cells.

Division only crosses the middle of the bird because vertebrates develop in a symmetrical bilateral way. Although one side may be mainly made up of ZW and the other of ZZ, previous research indicates that there is some kind of mixture of cells in the body of the bird.

However, each side of the bird could be essentially the brother or sister of the other. Genes that are not the ones that confer gender are also affected.

In mammals, a gene on the Y chromosome that stimulates the development of the testes and whose hormones regulate the development of the rest of the body controls the determination of bad. For this reason, it is so rare to see gynandromorphism in mammals, said Hooper.

Hooper does not believe that there is any reason to ensure that there is a greater probability of mixed gender among the Cardinals than other creatures, but their color contrast by genre gives them a particular notoriety.

The cardinal woman has a brown color and is quieter than men with their intense tones. In addition to the red color, male cardinals sing more often with more complex tunes, both to proclaim their territory and to attract women.

In 2008, Brian Peer, a professor of biology at the Western Illinois University of Macomb, Illinois, began studying a similar cardinal, with a split in two. Over the next two years, Peer made over forty visits to the yard of a biology teacher from a high school who was already retired. There was a bird feeder that drew a bird with the right half of a woman and the other half. to the left of the male – the opposite of Cardinal Caldwell.

Peer, an expert on the behavior of thrushes, hoped to see if the cardinal would behave more like a woman or a man. Unfortunately, he could never see the bird interact with others, although this did not coincide with the idea that the cardinal was alone; Many cardinals never manage to reproduce in nature, he explained.

For two winters, Peer observed the bird, but over time, a cardinal who defended his territory with badault expelled him from the backyard of the teacher. The ginandromorph has never been reviewed.

Ginandromorphs are thought to be sterile, although the cardinal of Caldwell's court seems to have formed a pair with a male bird. Hooper pointed out that it is too early to know if this male is the father or the couple of the mixed bird, and he will remain for the mating season.

Even if the birds have a pair of ovaries, the only functional one is the left side – the feminine side of this cardinal – so in theory it's possible to lay eggs, Hooper said. He hopes that the offspring will have a conventional genetic burden because their egg cells would have only one bad chromosome.

Hooper mentioned that he would like to study the bird in depth, learn about its genetics and also understand the functioning of its brain: in gynandromorphs, a half of the brain is also a woman and the l? other half.

Singing birds have many more neuronal connections in their brains, which allows them to sing complex tunes, and Hooper wonders how this cardinal's brain, with a half-woman and a half of a man, could affect the ability and produce songs, as well as their desires to do so.

"I guess there's simply no complete neural network producing a song or the right hormonal badtail circulating in the brain to motivate the bird to sing even if it could." Hooper said in an email.

Butterflies can also be ginandromorphs, said Josh Jahner, a postdoctoral researcher at the University of Nevada, on the Reno campus, that it is half or half, or even in more varied proportions.

In her research, Jahner found that the wings of gynandromorph butterflies are similar to those of common butterflies, although the colorings of males and females appear in the same insect. However, the bads of each gynandromorph are different from all others, Jahner said. Knowing why this happens could be useful for scientists to understand the rules of development.

Shirley Caldwell appreciates for her part the attention and the opportunity to observe the extraordinary cardinal and look for patterns in her daily activities. "It has been very rewarding to know more about the bird," he said. "It's a unique experience in life, it's fun."

* Copyright: 2019 The New York Times News Service