Nestlings are young birds that have recently hatched from their eggs. They are typically born with closed eyes, bare skin, and are entirely dependent on their parents for food and warmth. Nestlings remain in the nest, where they are cared for until they develop feathers and can regulate their body temperature. As they grow, nestlings undergo several stages of development, eventually becoming fledglings. Fledglings are young birds that have begun to grow feathers and are preparing to leave the nest. This transition is crucial for their survival, as they learn to find food and evade predators in their natural habitat, such as forests or gardens.