The red knot shorebird is a tough, long-distance flier that migrates yearly from the Arctic into the Southern Hemisphere and back. For decades, the bird has been at risk because its food sources, such as crab eggs, have declined in the feeding grounds along its migratory route.

Now an alarming discovery by an international team of scientists, published this week in Science, shows that the effects of climate change on the robin-size shorebird may hasten its extinction.

“It’s even worse than we thought,” says Michael Reed, a conservation biologist and bird expert who teaches at Tufts University outside Boston. “This is going to increase their extinction risk, and the red knots are already in the highest risk category.”

The study found that