Hybridization among these species is notable within vertebrate groups. Such occurrences typically take place between recently diverged populations, with the most recent common ancestors of the Blue (Cyanocitta cristata) and Green (Cyanocorax yncas) Jays estimated to have existed at least 7 million years ago.
“We’ve been working hard to engage with the community,” stated Brian Stokes, a graduate student at the University of Texas at Austin.
“While historical instances of vertebrate hybrids have often been linked to human influences—like the introduction of invasive species and recent range expansions—this particular case seems to have emerged due to climate shifts prompting the overlap of both parent species.”
During the 1950s, Green Jays, a tropical bird native to Central America, were limited to areas from Mexico to southern Texas, while Blue Jays, a temperate species found in the eastern U.S., extended westward to Houston, with minimal interaction between them.
However, their ranges have since converged around San Antonio as Green Jays migrated north and Blue Jays spread westward.
Stokes, who is focused on researching Green Jays in Texas as part of his PhD, actively monitors various social media platforms where birdwatchers share photos of sightings. This was one of several methods he utilized to capture birds, take genetic blood samples, and then release them back into their natural habitats.
One day, he spotted a rough image of an unusual blue bird featuring a black mask and white chest shared by a woman in the suburbs northeast of San Antonio. Although resembling a Blue Jay, it was distinctly different. The backyard birder welcomed Stokes for an in-person sighting.
“On our first attempt to capture it, the bird was quite elusive,” Stokes recounted.
“But the second day proved to be much more fortunate.”
Using a mist net—a long rectangular mesh of black nylon thread stretched between two poles, almost invisible to birds in flight—Stokes was able to successfully catch the bird on the second day after previously capturing and releasing dozens of others.
He quickly took a blood sample from this peculiar bird, allowing him to facilitate future research.
Interestingly, the bird vanished for several years, reappearing in the woman’s garden in June 2025. The reason for its return remains a mystery.
“I can’t explain it, but it felt like pure chance,” Stokes commented.
“Had it been two houses down, it likely wouldn’t have been reported at all.”
Investigations revealed that the bird is a hybrid descendant of a male Green Jay and a female Blue Jay.
It closely resembles other hybrids produced through researcher crossbreeding of Green and Blue Jays in the 1970s.
“Hybridization is likely far more prevalent in nature than researchers recognize, as we often miss these events happening,” Stokes expressed.
“Furthermore, in many species, physical barriers may prevent interactions that could lead to mating because we’re not actively observing.”
The team’s publication appears in the journal Ecology and Evolution.
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Brian R. Stokes and Timothy H. Keat. 2025. Intergenerational hybrids between historically isolated temperate and tropical Jays after recent expansion of the scope. Ecology and Evolution 15(9): E72148; doi: 10.1002/ECE3.72148
Source: www.sci.news
