Rare blue-and-green hybrid jay spotted in Texas is offspring of birds whose lineages split 7 million years ago

For the first time, scientists have observed the wild hybrid offspring of a blue jay and a green jay during a study near San Antonio, Texas.

The hybrid bird is the product of two species whose habitat ranges began to overlap a few decades ago, according to a study published Sept. 10 in the journal Ecology and Evolution.

"We think it's the first observed vertebrate that's hybridized as a result of two species both expanding their ranges due, at least in part, to climate change," study co-author Brian Stokes, an ecologist at the University of Texas at Austin (UT Austin), said in a statement.

Blue jays (Cyanocitta cristata) and green jays (Cyanocorax yncas) are both types of corvids, a family of birds that also includes crows and ravens. Despite their similar names, blue jays and green jays aren't very closely related. They don't share a genus, and their lineages split about 7 million years ago.

Green jays have historically lived in warm, tropical areas of Mexico, Central America and southern Texas, while blue jays can be found across much of the eastern U.S. as far west as Houston. Over the last several decades, warming temperatures have enabled green jays to expand their range farther north, while both climate change and human developments have pushed blue jays farther west. The two species now coexist in part of Texas near San Antonio.

Stokes, who studies green jays at UT Austin, found the hybrid jay through social media in 2023. A birder from the San Antonio area had posted a photo of the unusual bird from her backyard, and she invited Stokes to her house to observe the bird more closely over two days.

"The first day, we tried to catch it, but it was really uncooperative," Stokes said. "But the second day, we got lucky."

Stokes managed to catch the jay in a mist net — a thin mesh suspended between two poles that's hard for birds to see. The bird had blue plumage but similar facial markings to green jays, and it could produce calls of both species. Stokes took a blood sample from the bird and placed a band on its leg to help identify it in the future, then released it back into the wild.

A genetic analysis of the blood sample showed that the bird was probably the offspring of a female green jay and a male blue jay. The hybrid bird is the first known crossing of these two species in the wild, but in the 1970s, scientists bred a green jay and a blue jay in captivity. The wild hybrid's appearance is similar to the taxidermied captive-bred bird, which is now part of the Fort Worth Museum of Science and History's collections.

Despite this being the first reported sighting of a hybrid of the two species, the jay was at least a year old when Stokes tagged it. Over the next two years, no one else reported spotting the jay, but it returned to the same San Antonio-area backyard in June 2025.

If there are other hybrid jays, they might be difficult to detect — outside of San Antonio, few people live in the region where the two species overlap, so the odds of someone spotting a hybrid are low.

"Hybridization is probably way more common in the natural world than researchers know about because there's just so much inability to report these things happening," Stokes said.