An anonymous reader writes: The vividly colored green jay is found in parts of South and Central America, Mexico and a limited portion of southern Texas. But since 2000, the tropical bird’s territory has expanded north by hundreds of kilometers — more than 100 miles and about 2 degrees of latitude — along the Rio Grande and up toward San Antonio.
While monitoring social media for green jay sightings in May 2023, Stokes came across an intriguing post on a Facebook group called Texbirds. A woman in a suburb of San Antonio shared a photo of an unusual bird that didn’t look like any jay Stokes or Keitt had ever seen.
The researchers tagged the mystery bird and drew blood for genetic sampling. They noted that their study subject displayed distinct traits of both blue and green jays — which aren’t that closely related and split off from a common ancestor around 7 million years ago.
The bird had blue feathers on its back and tail and white spots on its wings, similar to a blue jay. But it lacked a blue jay’s spiky crown and had a spot over its eye that is one telltale sign of a green jay. The outlier followed a flock of blue jays and made similar calls. But it also produced the clicks and rattling vocalizations of a green jay.
Upon returning to the lab, Keitt and Stokes completed a series of gene analyses, comparing the DNA they’d collected with that of a blue jay, a green jay and other jay species, and determined the mystery bird was the offspring of a male blue jay and a female green jay.
To Leighton, the odd pairing is something of a “biological curveball.”
“Both of these jay species form long-term social bonds with a mate,” he explained. “We would expect them to be pretty choosy about who they form these pair bonds with.” What’s more, corvids are extremely smart, and blue jays and green jays look quite different from one another. They should have no problem telling themselves apart.
Perhaps, Leighton speculated, it was the end of breeding season and the birds were under pressure. “If they aren’t having good luck finding an individual in their own species that is also without a mate, then maybe there’s a higher risk of making a mistake,” he said.
