Effective rat deterrents?

I live in Southern California, and tree rats/roof rats are a fact of life. I’ve always managed to deal with the little outbreaks–sometimes bigger outbreaks–with snap traps.

However, something’s going on in the crawl space under the roof. I’m not sure that it’s rats, because they’re active in the day and that doesn’t fit the usual rat MO. But I also can’t set traps for them–the noise is coming from the least accessible part of the crawl space. Setting traps and checking them would be virtually impossible. If there are rats, I can keep setting traps near the crawl space entrance and hope to lure them closer, but it hasn’t worked thus far.

I’m told that rats can be deterred/driven away by intermittent flashing lights. Anyone know the straight dope on these? The sites that discuss them appear to be either trying to sell me a product, or filled with “some people say that…” weasel words.

Our red squirrel population has grown a lot in recent years, any chance it might be squirrels. I live in So Cal also and have been fighting a rat outbreak. I have caught at least 2 dozen since the first of the year. Mine seem to stay in wood piles and brush mostly.

It could be squirrels. As I said the behavior seems a little unlike rats, though I also did just get a rat in the access hatch trap. Could be I have both up there.

Muy gato !!!

Poison with desiccant! They eat it, they get really thirsty. They leave your attic in search of water and expire out of doors! (Should they expire indoors the desiccant insures they don’t become putrid and rot. They just turn to dust!)

I don’t know about flashing lights, but last year I had a problem with rats under my car hood. Two cars actually. I’ve placed a work light with an LED bulb under the hood when it’s parked in my driveway and they haven’t returned. So the flashing lights may work, unless the rats can get under insulation or something where they won’t see the light.

Even if I had a cat, I don’t think it’d get into the attic without a lot of help, which I decline to provide.

I would reconsider this. I’ve owned pet rats for over 10 years so I’m pretty familiar with their behavior, and you are correct that “active in the day” doesn’t really fit rats. They are mostly nocturnal and while they’ll sometimes move around a little during the day, to move to a more comfortable sleeping location or something like that, if you’re hearing a lot of daytime activity, I’d guess it’s not rats. My guess would be squirrels.

But in any case it seems like one of the first actions should be to close up whatever holes or gaps they’re using to get into the house. Broken soffit vents are a likely candidate.

–Mark

Closing up all holes is a bigger job than I can undertake on my own, partly due to the aforementioned difficulty of moving around in the crawl space, and I don’t want to spend the money to hire someone. That’s why I was interested in a method of scaring them away; but if they’re not rats maybe I need to reconsider everything.

Do you hear noises at night too? If you hear noise only during the day and not at night, I would say it’s almost certainly not rats.

–Mark

Well, my solution to everything vermin related is nasty little rat dogs.

Well, there definitely ARE rats up there, at least sometimes. I just got one yesterday. I’m starting to think though that there is also…something else.

Very cat? :wink:

Trim trees or other vegetation that might be providing rooftop access. I assume that would help with either rats or squirrels. I’ve never had squirrels in my attic … well, except metaphorically.

I have heard of people putting a fake snake on the roof to keep rodent out , I am not sure if it works. I would the rats would get wise when the snake never move.

Rats have very poor eyesight. Their main senses are hearing and smell. A rat would probably not even notice a fake snake.

–Mark

There you go TSBG, you’ll need real snakes. Use several of them.

No way. Then I’d have to get those gosh-darn snakes out of my gosh-darn attic.

But that’s the beauty of it, in the winter the gorillas will freeze to death!

I once had something squatting in my attic, as evidenced by the scratching noises coming from the ceiling. I installed some humane catch-and-release mouse traps, but nothing took the peanut butter bait. Then one day I was up in the attic and I got buzzed by a blackbird. Further investigation revealed it had gained entry through a rotten soffit vent and nested in the eaves. I had a summer of being woken up early every morning by hungry chick noises (the nest was right above my bedroom window), but by the autumn the fledglings and parents moved out and I was able to repair the vents.

tl;dr: might be birds.

I had noises in the attic once, and got out the stepladder to open the ceiling trap. As I was looking around with my flashlight, one of our cats climbed up the ladder, jumped to my shoulder and then into the attic. She came back a few minutes later with a dead mouse, looking very pleased. After that, any time I got the stepladder out for any reason she would hover around until she could climb up and check for mice.

I did find the tiny gap where they were getting in when I saw one climb the outside wall and squeeze in where some mortar had crumbled just where the soffit met the bricks. The cat managed to climb up the extension ladder onto the roof while I was fixing the mortar, but didn’t find any mice, so demanded to be carried back down and ignored the extension ladder from then on.