fledging

Fledging is the stage in avian development when a young bird develops feathers and strength sufficient for flight and leaves the nest. The term can describe both the process and the young bird that has recently fledged, known as a fledgling. In general, a nestling is still in the nest and heavily dependent on parental care, while a fledgling has departed the nest but may still receive food or protection from adults as it learns to fly and forage.

The fledging process involves growth of flight feathers and improving coordination. The timing of fledging varies widely by species and ecological strategy. In altricial birds, which hatch in a relatively helpless condition, fledging typically occurs weeks after hatching and is followed by a period of learning and practice flights. In precocial species, young are more developed at hatch and may disperse from the nest area sooner, though the term fledging is less commonly applied to them. After leaving the nest, fledglings are often cared for by parents for a time while they gain independence.

Ecological implications include increased mobility and reduced nest predation risk, balanced against ongoing vulnerability as fledglings learn to forage and avoid predators. Fledging success is frequently used in population and ecological studies as an indicator of habitat quality and reproductive success. In wildlife care contexts, observers distinguish between nestlings, fledglings, and juveniles to assess whether a young bird is on track to independence or requires intervention.