Sadly, most free ranging cats around here seem to specialize in hunting song birds, baby bunnies, and lizards. So, that’s too much collateral damage for rodent control for my situation.
One of my old cats developed a late-in-life interest in stalking birds. I seriously doubt the old girl could catch a fly, but we’re not taking chances. We only let her in the patio under supervision. If she starts tracking a bird, we scoop her up and stick her in the house. We are trying to train her that hunting birds has negative consequences for her.
They use ultrasonic repellers in the parking garage at my office, and there’s still pigeons everywhere and the occasional rat. This is anecdotal of course, but based on my limited observation, I don’t think they work.
No, they do not work, they are a waste of time and money, cats not worth much more for this purpose. ( i like cats) Modify the environment to make it less attractive to rodents. Snap traps or other traps are very effective is used correctly, however rats are shy about new things in the environment and take to some to get used to them.
I have had an ultrasonic repeller under my kitchen sink (to keep mice from squeezing in around the piping) for a decade or more. I am pretty confident it works. It may only work over a limited area, not a whole yard or garage. For a while, I put the device on my back step. One morning, there was a mouse sitting next to it awake, alive but unmoving. It did not even try to escape when I captured it in a cup. So, this one does seem to work okay in a small area.
Rats are everywhere; I should think almost every patio gets the occasional visit from a rat, albeit almost always unnoticed. I wouldn’t start thinking about repellents unless you’re seeing them regularly. Where I live, I glimpse one crossing my garden about once every three years or thereabouts. I haven’t taken any action to deter them but have not had any issues with them.
If there are not already snakes living in your property/neighbourhood, there is probably a reason: cities are a dangerous place for snakes (cars, cats, and people who don’t like snakes). Releasing captive-bred wildlife is not an option: if they are not native, they can become invasive and impact native wildlife. If they are native, they can introduce diseases to the wild population, and being born in captivity they may not be prepared to cope in the wild.
If you’ve only seen one rat in decades then it sounds like you definitely do not have a rat problem! I regularly see rats in my neighbourhood and they have never caused a problem - I usually see them after dusk foraging in my neighbour’s berry bushes.
I would say you have a rat problem if:
–You find droppings everywhere
–There’s obvious damage to your patio plants (that is, the rats are eating them) or your patio furniture (missing stuffing out of cushions, gnawed metal or plastic parts) or your irrigation system (gnawed plastic parts)
–You find a nest
– They’re trying to come in the house
But if nothing like that is going on, I would not worry. A few around is normal especially if there’s fruit trees, a compost pile, or a dumpster nearby.