Climate change is threatening birds' migration patterns, according to a new study.
Each spring, birds migrate from their winter hangouts to their breeding grounds. Birds know to begin migrating when the sun appears longer during the day, which happens the same way each time Earth goes through its orbit.
So, if the birds arrive at the right time, breeding grounds will be full of food from blooming plants and swarming insects. But the changing climate isn't as reliable as Earth's orbit, and it's throwing off when spring arrives each year. This could threaten whole bird species.
If spring is late, the birds show up when there's less food and worse weather. And if spring starts early, the birds show up after resources have already been picked over. Either way, it'll be harder to survive, and they'll hatch fewer chicks.
Researchers studied 48 bird species and found that while most of them have adjusted their schedules to match the new seasons, nine species of songbird have not.
The researchers noted this could be the first sign of a domino effect because as climate is altered, nature may not be able to keep up.