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 that is featherless or only partially feathered. As wing and tail feathers develop, the bird becomes a fledgling. A fledgling may leave the nest or remain nearby while still being fed by parents; the key event is the bird becoming capable of flight. The act or process of attaining this stage is called fledging. When a bird has fully developed flight capability and independence, it is described as fledged; the degree of independence can vary by species.

Fledge is used almost exclusively for birds. Hours, days, or weeks for fledging vary widely among species; small songbirds may fledge within two to four weeks after hatching, whereas larger birds such as raptors take longer. The term can also appear in broader, metaphorical senses to describe someone or an organization coming to maturity and independence, though in that sense it is relatively uncommon.