I believe this might be the 'Spicebush Swallowtail' butterfly. It looks very similar to the 'Pipevine Swallowtail' or the black version of the 'Yellow Tiger Swallowtail.' Mother Nature loves to fool us!
The angles below shows the butterfly 'mid-flight' - as it's landing on the clover - and then as it's perched. Be sure to double-click on the images to see them full size.