A female mammal carries her young inside her uterus before they are born (viviparous). This provides the unborn offspring with protection and so vastly increases their chance of survival.
A female nourishes her young with breast milk, which provides all nutrients needed for growth and protects against some diseases. Breast feeding also provides against a constant and safe place to feed.
General protection (Mammals)
A female, and sometimes the male, keeps an eye on thyeir young as they are growing up. This helps rto protect the offspring from predators and other harm. The young gradually learn from their parents how to look after themselves. However not all behaviours are learned; some behaviours are instinctive - animals are born being able to do them.
Once the eggs are laid, the parents sit on the eggs to incubate them. This keeps each egg warm until the chick inside has developed and is ready to hatch.
One or both parents leave the chicks in their nest to go out looking for food. they bring food back to feed their chicks.
General protection (Birds)
This includes building a nest (often hidden or in a place that is difficult for predators to get to), laying eggs that are camouflaged, and attaching or distracting predators.