This 'Grue Jay' Hybrid Looks Cool as Hell—but It's a Warning Sign

Meet the “grue jay,” a rare offspring of a blue jay and a green jay—two common species whose evolutionary separation took place 7 million years ago. The resulting bird’s feathers are a muted, fashionable blue. But the marvelous discovery belies the fact that its existence may be the product of climate change’s threat to bird life.

In a recent Ecology and Evolution paper, biologists at the University of Texas at Austin describe the odd jay in more detail, explaining how the blue and green jays’ ranges might have crossed for this hybrid bird to exist. According to their analysis, green jays—a tropical bird found in Central America—have been migrating farther north as a result of temperature changes. Eventually, their paths crossed with blue jays, a temperate species common in the Eastern