PORT ST. LUCIE, Fla. – An exceptionally rare yellow northern cardinal with a genetic color mutation was spotted and photographed in Port St. Lucie on Saturday morning.

Tracy Workman, who teaches photography at a homeschooling organization, said she first spotted the bird in her backyard on Oct. 3.

Nine days later, Workman saw the bird again; this time, she followed it for five minutes with her Canon T5i camera before finally capturing some photographs.

"Following a bird is, of course, not the best way to get pictures of it," Workman said with a laugh. "But, at first, I didn't believe I actually saw it. I was super excited."

Geoffrey Hill, a professor and curator of birds at Auburn University and an expert on bird coloration, said the bird in Workman's photographs is an adult male northern cardinal with a rare genetic mutation found in the species.

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Hill said the mutation found in the northern cardinal species acts as a "knockout of the redness pathway" in the bird's DNA, blocking the normal red pigment and replacing it with a vibrant yellow color.

Only three yellow cardinal sightings are reported a year, making the bird's appearance a "one in a million" finding, Hill said.

The mutation is analogous to albinism found in humans, Hill said. Like humans, all birds have DNA that is subject to mutations.

"This phenomenon has been around forever, but now everybody is looking for them," Hill said. "This is good for habitat preservation. People are excited about birds for a minute."

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Workman gave the yellow cardinal the nickname "Sunny," she said.

"I thought it was a good name for a yellow cardinal in Florida," she said.

Thomas Webber, a collection manager of the Division of Ornithology at the Florida Museum in Gainesville, said the yellow cardinal makes up "well below 1%" of the entire cardinal population.

While some female cardinals can appear yellow or ochre in color, a male cardinal with true yellow pigment is far from common, Webber said.

"It's an extremely rare phenomenon," Webber added.

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For Doug Young, chief operating officer for the South Florida Audubon Society, a rare wildlife sighting like the yellow cardinal means an increase in appreciation for the world's most fragile bird populations.

A new report recently released by the National Audubon Society shows that 389 bird species are at risk of extinction because of climate change. If greenhouse gas emissions are not decreased by 45% by 2030, these species could be highly vulnerable to extinction.

"Getting the word spread about these rare sightings is a good thing," Young said. "It's a visual that gets people excited about birds and nature."

A yellow cardinal was also spotted in Alabama in February 2018. A professional photographer, Jeremy Black, asked to come to the woman's house who spotted the bird and captured footage that has circulated across the nation.

Follow Max Chesnes on Twitter: @MaxChesnes