This woman was going about her garden (partly paved), picking up something carefully with a plastic bag, without touching the object with her bare hands, popping it into the bag, and moving on. It became clear that she was collecting snails and slugs. Mostly dead, it appeared. Yes, she said, the pests were so fierce this year that she had sprayed some of her most precious plants such as peonies and foxgloves and certain lilies. The nightly predators are attacking, this year, plants they barely touched previously. And in herbs, she said, she had never seen such visitations among some of the stronger-smelling, such as chives and winter savory. (These she did not spray.) She picks up the dead slugs and snails, hammers the bag with a stone in case some are still alive. Then the bag is put into the bin.
She believes that this preparation she uses contains a bird-repellent and that no thrush or blackbird is going to be poisoned if it did pick up a corpse or still living creature, but she is being careful. For seedlings of chervil or other herbs in the cold frame, it is safe to use the little blue pellets. No bird will get at them, and no predatory slug or snail can get out by penetrating mole-like under the wood. The woman doesn't believe she has ever seen such a proliferation of the pests.
Pests? One William Derham, quoted in Richard Mabey's Nature Writing, an Oxford paperback, takes the presence of such creatures philosophically: "The fierce, poisonous and noxious creatures serve as rods and scourges to chastise us, as means to excite our wisdom, care and industry ... The wise author of nature, having denied feet and claws to enable snails to creep and climb, hath made them amends in a way more commodious for their state of life, by the broad skin along each side of the belly, and the undulating motion observable there. By this latter it is they creep; by the former, assisted with the glutinous slime emitted from the snail's body, they adhere firmly and securely to all kinds of superficies, partly by the tenacity of their slime, and partly by the pressure of the atmosphere. (From "The Great Variety and Quantity of all Things", Physico-Theology, 1713, 1754.
The Field once airily advised keeping snails in check in the greenhouse by procuring a couple of toads. Said also to keep down woodlice. Y