Oh geeze Becky, that's awful. I never knew that rats would do that. Our city is over run with rats and we get them too. They actually have dug big holes in my garden and the holes a lot of times go under the daylily plant. We usually put poison as deep in the hole as we can so no other animals get it. On occasion my DH will get his pellet gun out and hunt them, lol. It makes sense now when I think of it though because we have seen them underneath our bird feeder getting the fallen seed. So I guess they would eat daylily seeds then. Maybe if you didn't want to kill them your city may have traps that they could loan out to you to trap them.
