I have also had entire marigold plants ripped off in the same fashion. The good news is though, the LaRouge pepper and one of the yellow peppers are starting to come back! Little leaves are forming at the base of the stem! I hope the others come back too, although I do not know if there is enough time in the season for them to mature and produce peppers. I see the crows hanging out in my garden when I leave for work in the morning. The weird thing is, all I have seen around are chipmunks, squirrels, a bunny and a ton of birds and crows around, so I don't know if it is one of those or not. These plants were not very big yet as I recently planted seedlings. The whole plant gone except like a half inch of stem left. Then a LaRouge pepper and then a green pepper plant. All that was left was a stub of a stem left. I basically have had the same thing happen to me this year! I have had two yellow pepper plants ripped off one night. It does sound like an animal, not insects, if the whole plant disappears.

Southerners does this sound like armadillo? But if this guy is bothering your garden, it likely is bothering your neighbors as well. Perhaps you have some special southern california critter the rest of us don't know about. So the whole plant is just gone? Not cut off and lying there? I'd check with your neighbors. What works for me keeping them out is fencing in each bed with deer netting, stapled down at the bottom and pulled together and tied over the top to make a cage. It will kill for corn or tomatoes, but only tromples the plants to get to the good stuff. The raccoon usually isn't too interested in plants, just fruits/veggies. The groundhog nibbles the tops off plants she likes (including broccoli, sunflower, appendaged water leaf and others), leaving a few inches of stub behind.

And I've never seen the dirt piles you describe. But I've never had to fence my peppers, which neither the groundhog nor the raccoon show any interest in, either the plant or the fruits. I fence a lot of things in to keep the critters away from them. I live with a resident groundhog and raccoons (one just came out yesterday, trailing four babies behind her, not good news!).

Do cat birds eat runner bean plants