Both deer and rabbits can do substantial damage to landscape plants. Even field mice can do a substantial amount of damage to landscape plants.
Field mice can usually find enough food outdoors even during the winter.
But they cause big problems in the nurseries because they get into the greenhouses and plastic huts. The only thing in there to eat are plants. Of course a mouse doesn't eat much, but they eat the bark off the stems, girdling the plants and killing them. Nurserymen use rodent bait that is designed to hold up under the moist conditions found in greenhouses to control these pests. Rabbits are also a king size headache for nurserymen, golf courses, and homeowners.