Merriam-Webster Collegiate Dictionary - fledge

 verb  (~d; fledging)  Etymology: ~ capable of flying, from Middle English flegge, from Old English -flycge; akin to Old High German flucki capable of flying, Old English fleogan to fly — more at fly  Date: 1566  intransitive verb of a young bird to acquire the feathers necessary for flight or independent activity; also to leave the nest after acquiring such feathers  transitive verb  1. to rear until ready for flight or independent activity  2. to cover with or as if with feathers or down  3. to furnish (as an arrow) with feathers