Most people call the inner musical repeater the earworm. I call it my mental jukebox. It has a few old scratchy records that the drunk at the bar tiresomely plays every night, plus a much wider row of buttons that push automatically for no obvious reason.
On this morning’s walk I became conscious of an unusual spontaneous selection in my jukebox, and then heard a bird running his jukebox.
Ping! Our mechanism is the same as the bird’s mechanism. It repeats a standard melody with slight variations. Most birds have a shorter row of buttons, but always more than one. At least a morning song, warning song and courting song.
Polistra's Mill 