PLZ HELP ASAP ITS DUE SOON I WILL GIVE BRAINLESTS They shut me up in prose

They shut me up in Prose -
As when a little Girl
They put me in the Closet -
Because they liked me "still" -

Still! Could themself have peeped -
And seen my Brain - go round -
They might as wise have lodged a Bird
For Treason - in the Pound -

Himself has but to will
And easy as a Star
Look down opon Captivity -
And laugh - No more have I -

*How is the speaker like a bird lodged for treason in
the pound?