Precocial Birds

• Some bird species, such as ducks and shore birds, are precocial, meaning they give birth to young who are ready to leave the nest almost immediately after breaking out of the egg. Upon hatching, the chicks are covered with down and their eyes are open.
  
  

Altricial Birds

• The majority of birds, including all perching birds, are altricial, meaning that their young are hatched with little or no down, with their eyes closed and requiring parental feeding until they further mature, according to the Birds of Stanford website at Stanford University.
  
  

Parental Care

• In species where both parents care for the young, the male often gathers food while the female spends more time brooding--keeping the baby birds warm, sheltered and safe from predators.
  
  

Feeding

• In some species, the female is the main provider of food for the young, but in others the job is exclusively the male's, or is shared. Some carry food to the young, while others regurgitate food they have eaten when they return to the nest.
  
  

Nest Cleaning

• Particularly for those birds whose young must mature before they leave the nest, it is necessary for the parents to rid the nest of waste products to prevent disease. The young of many types of birds produce a fecal sac, making it easy for the parents to dispose of, says Ornithology.com.