This Rare And Beautiful Bird Is Known As A Gynandromorph - Both Male And Female

"One of them described it as 'seeing a unicorn,' and another described the adrenaline rush of seeing something so remarkable."

Stephanie

• Published in Animals
• February 28, 2022

Bird researchers in Rector, Pennsylvania, made a discovery in September 2020 that left them in awe. They spotted a rose-breasted grosbeak with all the markings of a male on its right side but female markings on its left!

You see, the markings on a rose-breasted grosbeak, or Pheucticus ludovicianus, are very specific to their gender. A pink spot on the breast and pink "wing pit" with black feathers are typically signs of a male, whereas brown and yellow plumage is generally a female trait.

Annie Lindsay was out capturing and banding birds with some of her team from Powdermill Nature Reserve when one of her colleagues spotted the bird and called out to her. Annie knew immediately what they had found; a gynandromorph - a half male, half female creature!

These kinds of birds are very scarce, and during her career, Annie has only ever seen one other like it. And in its 64 years of bird banding, Powdermill's Avian Research Center has recorded less than ten bilateral gynandromorphs.

In fact, gynandromorphs, in general, are extremely rare. However, they are not always easy to recognize, so they could indeed be more common than we think.

"The entire banding team was very excited to see such a rarity up close and are riding the high of this once-in-a-lifetime experience," said Lindsay. "One of them described it as 'seeing a unicorn,' and another described the adrenaline rush of seeing something so remarkable."

"They all are incredibly grateful to be part of such a noteworthy and interesting banding record," she continued. "Bilateral gynandromorphism, while very uncommon, is normal and provides an excellent example of a fascinating genetic process that few people ever encounter."

Bird researchers in Rector, Pennsylvania, spotted a rose-breasted grosbeak with all the markings of a male on its right side but female markings on its left.

According to the Oxford dictionary, the definition of a gynandromorph is "an abnormal individual, especially an insect, having some male and some female characteristics." Gynandromorphism is most common in insects, and the cause varies.

For example, in shrimp, gynandromorphy is believed to result from an epigenetic modification that takes male cells and makes them female. However, in birds, it is more likely to occur when two sperm fertilize an egg that has two nuclei instead of one.

The egg can then develop both male and female sex chromosomes on either side. This means a bird with gynandromorphism could have testis on one half of its body and an ovary on the other.

It's unknown whether these birds behave more like males or females or if they are able to reproduce. And sadly, any research is difficult because these animals are so rare.

Annie Lindsay knew immediately that the bird was an extremely rare gynandromorph.

The beautiful bird's markings were split roughly down the middle.

The Powdermill Avian Research Center is an emerging national leader in avian research. It works hard to ensure the best practices for tracking birds.

With the beautiful rose-breasted grosbeak now banded and tracked, hopefully, the stunning bird can help to shed some more light on the way gynandromorphs live. We can't wait to find out more about these fascinating creatures!

Stephanie