A common swift leaves its nest in Europe in August and does not touch anything solid again until it returns the following summer. Ten months. No branch, no ledge, no ground.
It eats in the air, catching insects mid-flight. It gathers nesting material in the air. It mates in the air. One tracked bird landed for four nights across an entire year; the next year, two hours.
Sleep happens up there too. At dusk it climbs two or three kilometres and glides slowly back down through the night, wingbeats falling away.
Its scientific name, Apus, means footless. On the ground it is nearly helpless — the legs are too short to launch from flat earth. Everything that reads as a deficiency down here is the price of a body built for somewhere else entirely.
The sky isn't where it travels. It's where it lives.