I live in the suburbs and in the last few years have seen an exploding rat population outdoors on my property. It began when my neighbors got chickens back in 2020; when home-steading and DIY food management began taking off. They ended up eventually removing the chickens and scraps, but the rats stayed and their population keeps growing despite the removal of food.
I've trapped and killed SO many of these pests, but they keep increasing and each generation seems to be smarter about traps than the previous. The traps have become ineffective at this point. I've tried many of the suggestions seen on Youtube and they fail or some of them are just downright messy/impractical (the bucket).
The most effective solution I came up with so far is building a custom wooden box that leaves just a small opening (like a tunnel) for the rat's head to get into to reach the bait. I used peanut butter as bait and a snap trap inside the box. I then cover the wooden box with leaves and stuff. This worked for a few months, but unfortunately it's not working any longer. On the last occasion it worked, the rat in the trap got cannibalized by another larger rat. Since then, I can see on my camera that the rats approach the trap, but they never enter. I've tried relocating it and everything, no luck.