Why birds build there nests at high places?

It has so many benefits: 1. Safety from other creatures. 2. Better view for searching for food for the infants. 3. When the infants will grow up, the parents can easily teach them how to fly from high places. 4. Infants will fear of falling down, so they won't come out when the parents are not around.

it's for protecting their eggs from predaters and other possible harms. and of course their children need a high place to learn to fly!;)

I think they want to protect from other creatures.

I think all of that you have mentioned are correct and also they don't want to get themselves or their babies eaten by a predator.