Notes on Book of Proverbs (Author Bishop Richard Challoner (ed.))
26:2 As a bird, etc: The meaning is, that a curse uttered without cause shall do no harm to the person that is cursed, but will return upon him that curseth, as whithersoever a bird flies, it returns to its own nest.
Original Douay-Rheims from Project Gutenberg - Massive cleanup of OCR problems and editing done locally.