Birds in the Southwest are Molting Earlier

Birds in the southwestern United States are changing their molting schedules. This is a big deal because molting is when birds replace their feathers. It's a key part of their yearly cycle. Researchers looked at data from bird banding over 13 years in southeastern Utah. They wanted to see if the timing of molting was changing over time. They checked both spring and fall molting seasons. They also looked at differences between males, females, and young birds. The study found that spring molting times were not changing much. But in the fall, birds were starting to molt earlier. This means they are replacing their feathers sooner than they used to. Climate plays a big role in this change. Things like El Niño, temperature, and rainfall all affect when birds molt. For example, warmer temperatures can delay fall molting. But more rain can make birds start molting earlier. This is the first study to look at long-term molting trends in North American birds. Over the past decade, birds in the western U. S. have been molting about one day earlier each year in the fall.