Researchers at The University of Texas at Austin have made a fascinating discovery: a bird that is a hybrid of a green jay and a blue jay. This unique bird may represent one of the first examples of hybrid animals emerging due to climate change. These two parent species have been separate for 7 million years, and their habitats didn’t overlap until very recently.
“We believe this is the first documented case of a vertebrate hybrid created as both species expand their ranges, partly because of climate change,” said Brian Stokes, a graduate student in ecology, evolution, and behavior at UT, who led the research.
Stokes pointed out that most known vertebrate hybrids have resulted from human actions, such as introducing invasive species or the expansion of one species into another’s territory—like polar bears and grizzlies. However, this particular hybrid seems to have developed as both its parent species responded to changing weather patterns.
In the 1950s, green jays, which are tropical birds native to Central America, barely reached south Texas from Mexico, while blue jays, a temperate species found throughout the Eastern U.S., ranged only as far west as Houston. They rarely encountered one another. Recently, however, the habitats of green jays have moved north, and blue jays have expanded west to converge around San Antonio.
As a Ph.D. candidate studying green jays in Texas, Stokes kept an eye on social media where bird enthusiasts post photos of their sightings. This was one of his avenues for locating birds to trap, collect blood samples for genetic analysis, and then release them back into the wild. One day, he stumbled upon a blurry image of an unusual blue bird with a black mask and white chest, posted by a woman in a suburb northeast of San Antonio. It resembled a blue jay but was unmistakably different. She invited Stokes to see the bird in person.
“On the first day, we tried to catch it, but it was really evasive,” Stokes recalled. “However, we got lucky on the second day.”
The bird accidentally became ensnared in a mist net—a fine mesh setup that birds often overlook while flying. Stokes had previously caught and released several birds, but this particular one finally ended up in his net on the second day.
After quickly taking a blood sample, he banded the bird’s leg for future identification and released it. Interestingly, after vanishing for a couple of years, the bird returned to the woman’s yard in June 2025. The reasons for this peculiar return remain unclear.
“I have no idea what drew it back; it seemed like sheer luck,” he said. “If it had landed just two houses down, it probably would have gone unreported.”
Through analysis conducted by Stokes and his advisor, integrative biology professor Tim Keitt, it was confirmed that the bird is a male hybrid offspring of a green jay mother and a blue jay father. This finding is similar to another hybrid created in captivity by researchers in the 1970s, which looked like the bird Stokes and Keitt studied and is now preserved at the Fort Worth Museum of Science and History.
“Hybridization is likely much more common in nature than we realize because many are not observed,” Stokes noted. “It could occur frequently among species that are physically isolated from each other and don’t have the opportunity to mate.”
The research was made possible through a ConTex Collaborative Research Grant from the UT System, along with support from the Texas EcoLab Program and Planet Texas 2050, the University of Texas at Austin’s grand challenge initiative.
While the researchers chose not to name the hybrid bird, others like the “grolar bear” (polar bear-grizzly bear hybrid), “coywolf” (coyote-wolf hybrid), and “narluga” (narwhal-beluga whale hybrid) have received catchy nicknames.
Summary: Scientists at The University of Texas at Austin discovered a hybrid bird resulting from the mating of a green jay and a blue jay, highlighting how climate change is driving species expansion and hybridization. This rare bird was spotted in a San Antonio suburb and represents a significant finding in the study of vertebrate hybrids. The research suggests that hybridization may be more common in nature than previously thought.
