So last week my wife and I discovered some evidence of mice fooling around in our kitchen at night (e.g. shuffled cleaning supplies under the sink, hoarded dog food, and of course their droppings). After a little research, I decided to get the classic spring-style mouse traps. I set them with some peanut butter and after a night or two, I woke up to a dead mouse. After that, I cleaned up and set traps again. Things were quiet for a few days but then we got another hit. A second dead mouse captured. We were happy up until this point because we figured it was just one mouse but since we got the second one, I had to ask myself "when do I stop setting traps?" and "did the mouse come in because it smelled the peanut butter set trap?". It's sort of a catch 22 now. I am afraid that the mouse got in "because" I had peanut butter out (as part of the set trap). I'm afraid that if I keep setting traps that I may just be inviting these little guys in. Suggestions?
Setting traps will kill what you have, but you still have the problem of the mice getting in. you need to figure out how they are getting into the house. Mice can get through incredibly tiny holes, so it might be a chore to find them all. But as you find holes, seal them up. Steel wool is useful for this as they don't like chewing through it.
I personally go with 'forever'. I've got a good-size house, on a little bit land, and a garage door that I leave open for fair amounts of time each day in good weather. I'm ALWAYS going to have mice getting in, even though I've patched every hole I can find. It's just sort of inevitable at this point. So I keep the snap-traps under the sink and in the basement. I check them every couple of weeks, change the bait (I like cheese) now and then, and I get a few mice every year.
But no major infestations, and they don't seem to get past my initial trap points, so I don't get them in the pantry or anything.
According to the CDC's website, keep putting out the mouse traps and after five straight days of no mice, you should be in the clear. I did that in our attic and it seemed to do the trick --- and yes, there is always more than one... we caught 5 in 5 days. Three traps were left with peanut butter and no catches. After 30 days, I put out two traps again just to make sure and after five days there were no more catches. I recommend the 5 day rule.
Oh, and my recommendation with the snap traps. You don't have to touch the trap/mice if you put the trap in a small box (shoe size or smaller) before putting it in your basement/attic.
For what it's worth, I decided to contract with a pest control company for ongoing service. Periodically they refill the bait containers in the basement, and this has been sufficient to keep any mice from nesting in the attic. I don't like bait a lot -- among other things I worry about a poisoned-but-not-dead-yet mouse being found by a cat -- but it has been effective.
Reportedly, old style snap-the-neck traps are actually the least painful killing trap, but of course those have to be more actively maintained. Nonkilling traps are a nice idea but you have to empty them somewhere before the mice starve; I think what I really want is a nonkilling trap that sends email when it has caught something.
Warning: Mice often carry ticks, and in some areas ticks can carry things like Lyme disease. Be careful when disposing of carcasses. I've been tempted to put out Daminix as well, though it isn't cheap.
I have had similar issues in my house. First you set out traps until no mice come. Whether that is 1, 2, or 100. Peanut butter is a bit smelly but mice have good noses and habits. So if it is working you have to go with it - if you are attracting more, well so be it because they are going to smell something and will come into your house for just water.
The best way to deal with the infestation is to attack the perimeter. If you walk around the outside of your house you should see their dens (tiny holes usually right at the walls). You drop poison pellets down these holes. If you get certain brands these pellets are large - break them up so they can be carried easily. Monitor if the poison bait is moving. Keep on laying it out until they quit taking it. Cover the holes and then monitor for new ones.
Here is the thing mice communicate and follow patterns - maybe not as well as ants but pretty darn good. If there are 20 mice that understand there is a hole in your house and food in a room - they will get to that room. Cover the hole and they will gnaw their way in. Only when that conditioned group of mice is dead can you "start over". So you need to assume all mice around your house are conditioned for a food source in your house. Obviously easier to deal with poisoning them outside.
This is for if you have mice that you need to tackle outside as well as inside. Keep your house as clean as possible all food in containers. This won't stop them but helps prevent attracting more. Get steel wool and put it in any gaps and vents as mice hate it. Use pin traps cotton wool with peanut butter claps pin on cotton wool. It will put firing trap every time. Poison isn't a good idea inside your home as if the die near a hot water pipe etc. the whole house will smell. Would look into a drop self resetting trap in loft. You can leave for three or four days and check. Hopefully just three. If they have nested in house, a female can have 6 pubs 10 litters a year and each of them are sexually mature in 2 weeks. I had them in past. They say if traps have not been active in five days you're clear. But you should have three or four set traps in every room. Only then if the traps are non fired you're clear.