A Rare Breed

Birder has once-in-a-lifetime encounter with Cardinal

Photo courtesy of Jamie Hill An incredibly rare bilateral gynandromorph Northern Cardinal — essentially, half-female half-male — was cited over the weekend in the Grand Valley area. A similar bird in Erie was featured in the New York Times and National Geographic back in 2019.

An exceedingly rare half-male, half-female Northern Cardinal has been observed in the Grand Valley area.

Jamie Hill of Waterford said in a Facebook post that he’s been birding for 48 years and said what he saw Saturday was a “once-in-a-lifetime, one in a million bird encounter!”

The scientific name for the bird is “bilateral gynandromorph Northern Cardinal,” he explained.

Hill said he was with Annette Smith, whose mother said a friend had a bird coming to the feeder that appeared to be one half of one species and one half of another

“This really piqued my interest since I wasn’t sure if she was referring to a hybrid, or a much rarer gynandromorphic bird, a bird that is 1/2 male and 1/2 female,” Hill wrote. “We immediately tracked down the homeowner by phone and were told it was a male Northern Cardinal that ‘had some white on its breast.'”

The property owner, who Hill said has requested anonymity and no visitors, sent them a cell phone picture taken through a window of the subject bird and Hill said it was “immediately apparent that this was… indeed a cardinal with extremely rare bilateral gynandromorphism, which means it is genetically half male and half female!”

Hill explained that would mean the bird would have a functioning ovary on its left side and functioning single testis on the right.

“Theoretically, this bird could either mate with a normal male cardinal and lay fertile eggs,” he wrote, “or it could mate with a normal female cardinal and father her eggs!”

A 2019 National Geographic article highlighted a similar sighting in Erie.

That article about the Erie “half-sider” cites Daniel Hooper, who at the time was a postdoctoral fellow at the Cornell Lab of Ornithology.

“Cardinals are one of the most well-known sexually dimorphic birds in North America–their bright red plumage in males is iconic–so people easily notice when they look different,” Hooper told National Geographic.

That article gives us some background on — biologically — just how this bird came to be: “Hooper says sex determination in birds is a little different than in mammals. In mammals, he says, males have one copy of each sex chromosome (X and Y) while females have two copies of the X chromosome. In birds, it’s the opposite. Their sex chromosomes are called Z and W, and it’s the females that have a single copy of each (ZW), whereas the males have two of the same (ZZ). Sex cells’ nuclei, including sperm and eggs, usually have only one copy of either chromosome — males produce only Z-carrying sperm, and females produce either Z- or W-carrying eggs. Gynandromorphy like that in this cardinal occurs when a female egg cell develops with two nuclei — one with a Z and one with a W — and it’s ‘double fertilized by two Z-carrying sperm.”

Hill said that in addition to National Geographic, the New York Times also picked up the 2019 story.

“That’s how rare and interesting this condition is,” he said. “Could this bird be the same individual as the Erie, PA, bird? Possibly — their bird was female on the left and male on the right, too.”

The homeowner granted them an opportunity to try to come and photograph the rare bird.

“During our 1-hour stay, the bird came to the feeders only once with 5 other cardinals,” Hill wrote, “but thankfully it perched out in the open briefly in two other trees and I was able to shoot about 50 images.”


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