All models are wrong, but some are useful. Thinking of evolved features as having a purpose is wrong, but it is also incredibly useful.
Why do we have eyes? In some sense, there is no reason, just a sequence of random coincidences, combined with a slightly non-randon bias refered to as “survival of the fittest” (itself an incorrect model).
However, saying that we have eyes to see has incredible explanatory power, which makes it a useful model. Just like Newton’s law of Universal gravity. We’ve known it that is wrong for a century at this point, but most of the time still talk as if it’s true, because it is useful.
No. There haven’t been any real birds since the US government exterminated them in the 60s. Any “bird” you see today is a surveillance drone.