early casualty

When we built the garden fence, we used rabbit-proof fence about 70% of the way around.  The rest of the fence was well-embedded in the ground and did not appear to have any holes big enough for any of the hordes of rabbits running through our neighborhood.

Or so we thought.  The peas and beans have not been touched, but something chewed through the stem of one of the hop plants.  I am skeptical that the Willamette will make it, and I am now worried about all the rest of my tender plants just starting to make my garden look good.

I can't think of what else would such eat things.  Squirrels? Birds?