All birds build their nests differently, so their really is no straight answer. You would need to specify the type of bird.
Examples:
Eagles will build their nest with big sticks, and chickadees line theirs with moss. Weaver birds weave little hanging domes completely out of grasses, robing use sticks grass and mud, and humming birds usually use things like moss, down, fur and dryer lint.
a bird's nest is made up of straws and twigs .
It is made up of from dried grass
Bird's nest soup is a Chinese delicacy. It is made from the nest of a swiftlet, a bird in southeast Asia.
Sometimes they can make out where a nest came from or if it is man-made or not. They will probably live there if they don't have a choice, but some birds would rather build their own nest.
It is literally a birds nest made from edible fibers. Usually a swallow's nest :)
The nest was built by birds.
it looks like a birds nest
Because the design is based on a birds nest. If you look at the contruction of an actual birds nest it is very similar to the bird cage. Especially if viewed from the air.
A nest is often made of organic material and it is where birds lay their eggs. A roost is a place with support where birds commonly gather, not necessarily for laying their eggs.
Te specific study of the birds nest is calle "ornithology".
A birdbox is another term for a nest box, a man-made box provided for wild birds or small animals to nest in.
If the bird built it then it is generally called a nest. If it was made for the bird by a human it is generally called a birdhouse.
Birds mate after and before making a nest
Nestle has 3 birds in a nest on a branch