Confession! I have a persistent population of rats. They live in the scrub behind our back fence and slip over the fence during the night to eat any fallen food from the ground. I have to be very careful not to leave food lying around.
Every few weeks I rebait the trap and usually catch a few, but of course the really wary older rats are too clever for that little ruse. They won't touch baits, and although I'm scrupulous at cleaning up spilt food when I'm trying to catch them, they're amazingly smart.
Some time ago I realised they were shinnying down the 40cm long wire hook my sprout bag hangs on, and nibbling at the sprouts. I kept trying new places to hang the thing, only to see telltale bag-holes a few days later.
So I did this:
For a little extra detail, here's a close-up of the top arrangement:
The silver thing is an upturned stainless steel bowl bought cheaply from one of those two-dollar stores. I made a hole in the bottom and slid the wire through (after straightening it temporarily). Then I wrapped a rubber band around and around the wire just below where I wanted the bowl to sit. The rubber has a good purchase on the wire, so it doesn't tend to slide down, but to make sure, I added a layer of glue. Then I sat a disc of foam matting (purpose-cut and also threaded over the wire) to help ensure the stainless steel bowl doesn't tip too far when a rat climbs on top of it.
Since rats are coming along the beams in the shed roof and then clambering down (rather than jumping onto the bag from below) this is an effective barrier. They can climb onto the bowl but they can't get over the lip of it to reach the wire again.
There have been no more rat raids on the hanging sprouts!