Jeremy Black, an Alabama wedding and wildlife photographer, recently spent five hours in a friend’s back yard in the hope of capturing an image of what he called “the most captivating cardinal in Alabaster, Alabama.”

But that description sells this bird too short. The northern cardinal that Black ended up photographing was not the usual deep red of males but dazzlingly yellow. It could easily claim to be the most captivating bird in the nation — or at least on the Internet. Black’s photo, which was shared on the Facebook page of the Naturalist’s Notebook, promptly went viral.

“As soon as it landed, I was star-struck,” Black told National Geographic. “It kind of took my breath away a little bit.”

Black said in a Facebook post that he learned about the bird from a friend, Charlie Stephenson, a longtime birdwatcher who had spotted the sun-hued fellow at her feeder. At first, she told Al.com, she figured it was a species of yellow bird she had never seen before. Then she realized that the creature, with its black mask and crested head, looked just like a cardinal — just one of a different color.

This coloration is not unique, but it is aberrant, according to a 2003 research paper on what at the time was said to be the first-ever reported yellow northern cardinal in the United States. It was a specimen collected in 1989 in Baton Rouge by scientists at Louisiana State University. Researchers who studied its feathers concluded that the bird had a genetic mutation that impaired the metabolic processes that normally make red feathers out of the carotenoid-rich yellow and orange foods in a male cardinal’s diet.

Geoffrey E. Hill, an Auburn University professor who co-wrote that paper, told Al.com that the Alabama bird probably has that genetic mutation.

It is “a one in a million mutation,” said Hill, who added that he had never seen a live yellow cardinal in 40 years of birdwatching.

Another possible explanation, a National Audubon Society expert told the organization’s blog, is a dietary deficiency.

Rare though they are, yellow northern cardinals seem a bit more common with the advent of digital cameras and social media. A pair was spotted in Kentucky in 2011. Cindy Morgan, a Wynne, Ark., resident who commented on the Facebook post about the latest sighting, said one had visited her feeders in fall and winter for three years in a row.

Posted by Cindy Morgan on Monday, March 24, 2014

Stephenson, understandably, says she would like her yellow visitor’s fans to confine their admiration to the Internet. She told Al.com that she’s keeping her precise location secret to prevent birders — who are known to travel far and wide for a rare sighting — from flocking to her back yard.

Read more: