'Remarkable bird': Couple finds rare half-male, half-female cardinal
A Pennsylvania couple is used to finding birds in their backyard.
But after 25 years of attracting birds to their Erie backyard, Jeffrey and Shirley Caldwell say they were surprised to find such a unique bird appear.
The couple spotted a rare half-male, half-female cardinal.
They told National Geographic that the bird first showed up one morning a few weeks ago in a tree about 10 yards from their house.
“Never did we ever think we would see something like this in all the years we've been feeding,” Shirley Caldwell told the magazine.
The scientific name for this phenomenon is bilateral gynandromorph, which means half of the bird's body is male and the other half is female.
“This remarkable bird is a genuine male/female chimera,” Daniel Hooper, a postdoctoral fellow at the Cornell Lab of Ornithology, told the magazine.
The phenomenon apparently happens in all bird species, Hooper said. But it is rare.
“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 said.
Sex chromosomes in birds are called Z and W — unlike mammals, which have X and Y chromosomes. Male mammals carry X and Y chromosomes, while females have two copies of X chromosomes.
In birds, females have one of each (ZW) and males have two of the same chromosomes (ZZ).
Birds are not the only creatures where this happens, as the sex of insects and crustaceans also can be split.
Making this phenomenon for the bird Shirley Caldwell captured even more unique is that Hooper said the cardinal might be able to reproduce.
Shirley Caldwell said the bird eats black sunflower seeds and suet, and often appears with a male.
“We’re happy it’s not lonely,” she said, adding that she hopes she is "lucky enough to see a family in summer."