Most birds feed tiny insects, worms and fish to their babies to fuel their growth. Some birds, such as pigeons, parrots and penguins, regurgitate a small amount of digested food from its crop that they then feed to the baby birds.
Baby birds that depend on their parents for food are called altricial birds. These birds do not have feathers. They have close eyes at birth, making them unable to feed on their own. Precocial birds, such as geese, ducks, quails and cuckoos, are born with open eyes. They are covered with downy feathers after hatching. They can fly and hunt for their own food shortly after they hatch from their eggs.