To fly the nest means to leave your parents' home for the first time to go and live somewhere else.
When David started university he had to fly the nest and live alone.
All the children have flown the nest so Mum now has a lot of spare time.
A nest egg is an amount of money you have saved to use in the future.
Jane is going to use her nest egg to buy a big house by the sea.
The osprey in the photograph flew from West Africa to Scotland to breed. The egg in the nest is thought to have been her 50th egg to have hatched.