A nestling is a very young bird that hasn't yet learned to fly and still lives in its nest. These tiny birds depend completely on their parents, who bring them food and keep them warm. If you've ever seen baby robins with their mouths wide open, squawking for worms, you've seen nestlings.

Nestlings are different from fledglings, which are young birds that have left the nest and are learning to fly. A nestling still needs the safety of the nest. Its feathers might not be fully grown yet, and its wings aren't strong enough for flight. Watch a nest of nestlings and you'll see constant activity: parents flying back and forth with insects, worms, or seeds, while the hungry babies chirp loudly to get attention.

Sometimes people use nestle as a verb meaning to settle comfortably into something, like nestling into a cozy chair with a good book. You might also hear someone describe a village nestled in a valley, meaning it sits snugly among the hills, protected like baby birds in their nest.