I've had problems with them burrowing under the shed & then gnawing into it. There was no food or water source there whatsoever (garden tools & woodwork tools) they gnawed through every electric cable, & stank the place out with wee! Apparently they just wanted a protected secluded place for nesting. This is despite keeping all hay indoors, feeding my bun indoors, rat proofing the compost bin for garden refuse only, & we have wheelie bins!!
I eventually called the "pest control officer" when a young rat with no fear of me, was trying to get in the house by jumping against the patio doors. I really HATE poison, & am ashamed to admit that we had to resort to it eventually.
Completely agree with Thumps's post on every level. Rats, although they will be attracted if there is a food supply in the first place, somewhere to nest and raise young is of equal importance and as long as there is a food source in the locality they will happily stay in a garden with none - we had exactly the same problem. When all the bird food ran out from neighbours, and us, they ate all the frogs, snails, slugs and worms in the entire area. We too had to resort to poison in a
proper bait box and this is
essential in order to protect your buns and all other wildlife such as ground feeding birds, squirrels etc. I would also be very careful about where I put the bait box as it must be behind a wire/wood fence and away from your bunnies in every sense, this includes storage of the bait and handling it, wear gloves too.
Rats like somewhere dry - under shed, under decking (what happened here - went under our neighbour's decking) you will need to get your neighbours involved. Garden clearing, pruning, refilling in any holes they make, sealing up compost bins, removing any bird food etc are all part of controlling rat problems. We also used wire traps - prefer them as they are instant and usually we felt more humane, except we had one rat that broke three steel heavy duty traps in a row :shock: so we had to resort to bait in a bait box.
It was awful I won't deny it. My sister has always kept domestic pet rats so I found it very hard. My OH grew up with horses and stables and was more used to 'switching off' to deal with them. It's very sad indeed but unfortunately it has to be done.
You will find that if you take all the precautions and get a bait box back in at the first signs of trouble again (and/or traps) that any 'visiting' new rat will not survive long enough to breed again.