Heart not so heavy as mine
Whistled itself a tune
The heart whistles to itself—self-soothing, not performing. Dickinson contrasts this unconscious lightness with her own heavy self-awareness.
Irritated ear
She admits her annoyance at someone else's happiness. The medical term 'anodyne' (painkiller) follows—she's diagnosing her own emotional state.
Bobolink
A New England songbird known for rambling, musical calls. Dickinson uses it in 18 poems—her shorthand for natural, unforced joy.
Set bleeding feet to minuets
The formal dance (minuet) contrasts with 'bleeding feet'—pain transformed into grace without conscious effort. Notice 'without the knowing why.'
Ah, bugle
The whistler becomes a military bugle—a call to duty or reveille. She's elevated the stranger's casual tune into something ceremonial.