Climate change brings two jay birds together to create a rare hybrid

A backyard bird in suburban San Antonio turned out to be something extraordinary: the natural offspring of a green jay and a blue jay. The parents belong to lineages separated by about seven million years.

Their ranges barely touched a few decades ago. As shifting climate patterns nudged both species to expand, they finally overlapped – and this hybrid hatched within that overlap.

Biologists at The University of Texas at Austin analyzed the bird and traced its parentage to a green jay mother and a blue jay father.

“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,” said Brian Stokes, a graduate student in ecology, evolution and behavior at UT and first author of the study.

Two jay bird species meet in Texas

In the 1950s, green jays – tropical birds from Central America – barely crossed into South Texas. Blue jays, a hallmark of the eastern U.S., reached only as far west as the Houston area.

They almost never met. Since then, green jays have pushed north and blue jays have pushed west. Their maps now overlap around San Antonio.

Stokes notes that vertebrate hybrids often stem from human actions, such as introduced species or one species pushing into another’s range. Here, both species likely moved, spurred by changing weather patterns, and met in the middle.

Mystery bird draws closer look

Stokes was studying green jays in Texas and kept an eye on bird-photo posts to spot candidates for fieldwork.

One day, a user shared a grainy image of a blue-toned bird with a black mask and white chest. It looked vaguely like a blue jay, but something was off. The homeowner invited Stokes to take a look.

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

He set up a mist net – fine black mesh strung between poles – that passing birds rarely notice until it is too late.

The odd jay evaded the setup for a day while Stokes caught and released dozens of other birds. Then it blundered into the net.

Stokes drew a small blood sample, banded the bird’s leg, and released it. The visitor vanished for a few years. Then, in June 2025, it reappeared in the same yard. Why that yard? No one knows.

“I don’t know what it was – it was kind of random happenstance,” he said. “If it had gone two houses down, it probably never would have been reported.”

DNA confirms hybrid jay bird

Genetic analysis showed a male hybrid from a green jay mother and a blue jay father.

That pairing mirrors a lab cross from the 1970s, when researchers bred a green jay to a blue jay in captivity. The preserved specimen, which resembles the San Antonio bird, resides in a museum collection.

The new case is different in the detail that matters: it happened on its own, in the wild, where the two species now overlap.

Stokes emphasizes the distinction between this case and other hybrids. Polar bears and grizzlies, for example, mix where one pushes into the other’s territory.

Here, both species expanded, likely in response to climate shifts that reshaped temperature and precipitation patterns across Texas. Two moving fronts finally met, and a rare pairing followed.

Rare but likely overlooked

“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.

“And it’s probably possible in a lot of species that we just don’t see because they’re physically separated from one another and so they don’t get the chance to try to mate.”

Social media, neighborhood birders, and fast genetic tools now make it easier to catch the rare one that does.

Hybrids reshape bird populations

Hybrids are natural experiments. They can blur species boundaries, reveal which traits move between lineages, and hint at how changing climates will reshape communities.

In Texas, a tropical jay and a temperate jay now share neighborhoods. That overlap could bring more chances for crossing.

It could also prove a one-off if behaviors and breeding schedules rarely align. Either way, the sighting spotlights a broader biological story: as ranges shift, new interactions emerge.

Nature’s hybrids earn nicknames

The researchers did not christen this bird with a new name. Nature has a habit of coining nicknames for hybrids – “grolar bear,” “coywolf,” “narluga.” The team focused instead on documenting the tale from first photo to genetic proof.

A black-masked, blue-washed jay in a San Antonio backyard turned out to be the offspring of two species that rarely met until recently. It is a vivid, living snapshot of how climate-driven range shifts can bring distant lineages face to face.

As habitats warm and weather patterns wander, new edges form on species maps. At some of those edges, green may meet blue – and something new may take wing.

The study is published in the journal Ecology and Evolution.

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