Choirboy singing from balcony pulpitdetails

A beautiful boy chorister, or possibly a young lady by the costume and the long pointy fingers, is singing in a wooden pulpit or balcony high in the top-left corner of a page of sheet music (not shown). He or she has a red necklace and possibly a thurible. There are leaves that could be poinsetta but probably aren’t, a yellow songbird in a cage, and the pulpit bears the inscription Simon Dach M?CCIX, possibly a reference to the poet and hymn-writer Simon Dach (1605 – 1659) although the Roman numerals don’t seem to represent any likely date.