1. Pertaining to birds which are hatched with very small and soft feathers, well-developed legs, open eyes, the capacity to feed themselves, and the ability to leave their nests shortly after hatching: A nidifugous quail, duck, or pheasant is covered with down (hair-like feathers) when it is born, and as soon as it is dry, it is able to walk, follow its parents, and pick up its own food.
2. Etymology: from Latin nidus, "nest" + fugere, "to flee".