I do encourage hedgehogs, there's always water for them and two hog houses, one at each end of the garden. There's always a fair bit of healthy hedgie poo around the garden so I must be doing something right! Sadly they don't get the caterpillars because I grow my vegetables in pots and raised beds - due to the local cats who had a meeting and voted my garden the best toilet (I have to do a daily poo patrol) so I daren't grow things in the ground.
Something I've noticed this year for the first time is snail shells with half-eaten snails still in them. I discovered it is beetles eating them, which is a real bonus. I do seem to have less snails now, but either the beetles don't go for slugs or the slugs are just too prolific for them to make a difference.