What is the origin of the idiom "free as a bird" and when to use it?

The origin of the idiom "free as a bird" can be traced back to the inherent characteristics and behavior of birds. Birds are known for their ability to fly and move through the air with grace and agility, seemingly unhindered by earthly constraints. This metaphorical expression emerged as a way to capture the sense of freedom and unrestricted movement associated with birds. It draws upon the idea that birds are not bound by the same limitations as humans, such as gravity or physical obstacles, allowing them to soar and explore vast distances. It is commonly used when discussing situations or individuals who are unencumbered by responsibilities, obligations, or limitations.