> Even as they age, most bird species lack physical signs of getting old—their beaks don’t wrinkle, and their feathers don’t thin out or go gray. “Usually, you can't tell the bird is old just by looking at it,” says Kenn Kaufman, field editor for Audubon magazine. “In a few birds, they'll start to develop more white feathers in the plumage around the head, like a person's hair turning white, but that's not a common thing.” Unless a bird is banded, it’s hard to know its age.
> However, birds still go through the aging process. “The dogma in the field for many years was they don't really age, they just die,” Austad says. “But everybody that has studied them intensively can see some signs of them aging.”
https://www.audubon.org/news/why-birds-are-anti-aging-supers...