What extinct bird was found alive?

Imagine you're a curious individual, eager to learn about a fascinating discovery in the world of ornithology. You turn to your friend, a seasoned birder, and ask, "Hey, can you believe it? They say they've found an extinct bird, still alive and kicking! Which species is it? Is it a dodo, perhaps, or some other long-lost feathered friend that's managed to evade the march of time? I'm dying to know – what extinct bird has been rediscovered, still breathing and flapping its wings in the modern world?