Even an ostrich needs a nest : where birds begin
(Book)

How does a bird make its nest? Very carefully! Many birds build intricate nests out of twigs, leaves, feathers, mud, even dollar bills and clothespins. Some nests are gigantic, housing hundreds of birds or weighing as much as a car, while others are just large enough to keep one egg safe and warm. Whether simple or fancy, every species finds a unique way and clever place to raise its young.