Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
Describe the process for a bird laying an egg.

### Response:
When a bird lays an egg, the process is divided into three parts. Firstly, the egg is formed in the bird's reproductive tract. Then, the egg is covered in a protective coating known as the eggshell which is made from calcium carbonate. Lastly, the egg is laid from the bird's body and enters the nest.