Diagnostic Help Wanted

If I have to keep picking my tomatoes when barely pink in order to stop the evil little varmints that are taking bites out of them, I will soon kill someone.

Granted, my tactic so far has been one of distraction; I don't love my patio tomatoes (Extreme Bush variety, which is at least my favorite name), so they've become the martyrs.

I'm going to think out loud here for a minute. In an urban setting, what creatures are available that would take one bite out of a ripening tomato and then move on to the next to do the same? More information: some tomatoes are in a raised bed (1 foot up), and some are in containers (2 feet off the ground). Green tomatoes don't get attacked (yet). The riper the tomato, the more likely they will be attacked. Tomatoes that are lower on the plant are more likely to be bitten, but height doesn't seem to be a total deterrent. About 75% of the affected tomatoes are lower than most. The bottoms are usually, though not always, the area of first entry. When I leave the tomatoes on the vine, they'll be eaten little by little. When I take them off and put them on top of the compost pile, they're ignored and left to rot. Other veggies have not been affected. This includes: yellow squash, cantaloupe, peppers, cucumbers, greens, beets, and beans.

These are my guesses:
1) Rabbits.
2) Squirrels
3) Birds

If 1) then some chicken wire will help, especially if combined with cayenne. If 2), then it seems only cayenne would potentially help. I say potentially because it eventually stopped working with my birdfeeders and so I've stopped filling them. If 3), then I might get a blow-up Owl.

What's your opinion? What is it, and what should I do?