I am both heartbroken and mad - mad at myself - over this rabbit damage to the garden. After whacking away at the out-of-control forsythia, I left the copious trimmings in the area behind the veggie garden for later disposal. It looks like the culprits used this pile to boost themselves over the hardware cloth fence. And/or they squeezed through a gap at the corner of the fence. And/or simply scaled the fence, which was erected in a rather haphazard and flimsy way.
This all makes me feel like a bad gardener. It also makes me rethink the "backyard habitat" concept, or at least how I have implemented it. My yard is just too wild.