FLEDGE
Fledge is a verb used primarily in ornithology to describe the process by which a young bird develops the feathers needed for flight and grows toward independence. In practice, fledge can refer to the growth of flight feathers (the transition from down to contour and flight feathers) and to the bird leaving the nest to become self-sufficient.
In the life cycle of most birds, the sequence begins with the egg, hatching into a nestling
Fledge is used almost exclusively for birds. Hours, days, or weeks for fledging vary widely among species;