Zack Ciras of Colonial Pest Control talks about mice, and when the typical pest control methods don’t seem to work, including the behaviors that lead to that happening, and what pest control options remain for homeowners.

John Maher: Hi, I’m John Maher. I’m here today with Zack Ciras, quality manager with Colonial Pest Control. Today our topic is when mice don’t behave with typical pest control methods. Welcome, Zack.

Zack Ciras: Hey, John.

Typical Methods of Removing Mice

John: Hey. So Zack, what are the typical methods of ridding a home of mice?

Zack: Well, everybody knows the traditional wooden mouse trap, spring trap, or the snap trap as we call it. That’s one way. We’re going to set one trap, catch one mouse and you know where it is. You can remove it, you can deal with it. That’s the traditional way. Growing up, my father would have those under the sink and in the basement. And actually, my friend just texted me last night. He said, “What should I do?” I said, “If you have a wooden snap trap, put that out. It’s the quickest, easiest thing to do.”

Another mechanical way of controlling mice is glue boards. We don’t really love glue boards. They’re not very humane, but sometimes it’s the only thing that’ll catch them or it’s just a perfect spot for them. You’re worried about the spring trap with maybe kids around, but you can fold up the glue board so the kids can’t touch it. That’s another measure of mechanical control.

Professionally, the primary means of control is using anticoagulant baits. The anticoagulant baits are in temporary assistant locked cases, out of reach of children, pets. We always screw them down if they’re anywhere within reach of children and pets, generally accessible, and we want to make them nice and safe so he can’t pick it up and shake it.

Those anticoagulant baits are actually in solid blocks, so it’s even harder to pick up and shake. You might have grown up with the pellets. You peel off the plastic top of the little black square and there’s a whole bunch of pellets in there and you just put it everywhere you see mice. That’s not typically safe, not just for primary exposure for kids and pets who would pick it up and put it in their mouth and see what it tastes like, but also for mice can store those very easily in their mouth.

Then they’d run around, and before they get back to the nest, they stop and go, “Oh, look at all this dog food in the bowl. I’m going to drop these waxy pellets and grab some dog food.” So all the waxy pellets with the anticoagulant, the poison there, are next to the dog food or where they’re nesting in a baby’s winter boot in the middle of the summer. So the pellet baits aren’t really used very much anymore. But the solid blocks are pretty good for primary control. And the bait systems are pretty reliable, pretty trustworthy. And in most cases they just do the trick. You can have multiple mice feeding on one bait station and eliminate a lot of mice in short period of time.

How Mice Avoid Traps and Baits

John: Okay. So what we’re talking about today is when some of these methods that you just mentioned aren’t working for whatever reason. Can you go through some of the methods that mice have for avoiding these types of traps or why these types of traps maybe aren’t working in your particular case?

Zack: If I could interview every family of mice that I’ve seen do this, and it’s a growing population, it would be amazing. Mice, especially in areas of population density, in the cities, now growing in the suburbs outside of the cities, in these areas where people are gathered together and there’s probably a lot of food, maybe just in the trashcan, but the mice have access to that or people have gardens that at end of the summer you have way too many tomatoes and you just let them sit on the vine and say, “I’ll till that in, in the spring time.” That’s a food source. There’s acorns on the trees, there’s seeds on the flowers and the plants. There’s a lot of competing food sources that mice are more familiar with. It’s a more natural food source for them than a solid block of bait or even a soft satchel of bait or the pellets or the meal.

They have developed some sense of what’s normal food and what’s this other stuff that people are trying to give me that makes me a little nervous. So they’re avoiding eating the baits. Sometimes they’re actually avoiding eating the baits, but they’re going inside the bait station. I’ve seen on multiple occasions where mice are actually nesting inside of bait stations, so they’ll bring in insulation and cotton and string and make a little nest right next to the bait that I want them to eat and they just don’t touch it.

John: Wow. That’s really interesting. So what about the traps and things like that, that you mentioned? Are there ways that mice avoid those as well?

Zack: There are. Mice, if you look at the textbooks, mice are neophiles. They like new things. They’re very curious by nature. Where rats, on the other hand…the Norway rat is very cautious of new things. They’re neophobic, afraid of new things. So typically when we’re doing a rat treatment, a key thing that you want to do is maybe you put out some traps that you want to use to catch the rats, but you put delicious food on them, we’re using Slim Jims or bacon or different kinds of paste and peanut butter or whatever we think that they’re going to eat. We’re going to put those on the traps, but not set the traps. Let them feed off of the traps, you know, one, two, three days, maybe even more if it’s a real finicky situation, let them be comfortable with these new devices where they can now get a great meal and then go back after they’re comfortable, set the traps and catch them.

Mice, you typically don’t need to do that. But time and time again, we’re seeing mice avoiding snap traps, especially after maybe one’s been caught so they know what happened. They know what device took away their cousin or whoever. And we want to sometimes pre-bait the snap traps. But even with that, we’ve tried different kinds of traps, different kinds of baits, different methods of pre-baiting or not pre-baiting or just overloading or just having a couple. And I have night cam videos of mice going up to bait stations, snap traps, glue boards, sniffing them, maybe tapping them a little bit with their whiskers or their paw and just going, “You know, there’s something wrong with this. I’m going to skip it.”

And I don’t have a great explanation of how they learn to avoid them, especially in one house where there had never been mouse control there before, and in pretty wooded area. So we’re not thinking that it’s a family of mice that have been moving house to house to house and they go up to the bait station, they go up to the snap trap, and they’re comfortable feeding on the potato chips that we put in the bag around the snap trap to try to lure them in there, but they know just don’t touch that scary looking thing.

Do Mice Feed in Groups?

John: All right. That’s really interesting. Do you find that the mice tend to come out in groups? You said if one sees the other one get caught in a trap and now it knows to avoid those types of traps. Do they tend to come out in groups?

Zack: Mice have little clans. They’re pretty territorial. So you’ll have one dominant male, typically within a 25 to 30 foot radius around the nest. And that dominant male will protect its territory. The mother will protect the young until they’re a few weeks old when they can go out and find food on their own. They live in those little clans. When you have multiple colonies, multiple families of mice within a certain area, the dominant males will actually get aggressive with each other and fight each other. So I think within those small clans, the 25 feet around their nesting site, they might actually learn from each other, especially the young ones.

I think as they get older, there are more of their brethren that they could see, you know, this one made it, this one didn’t make it, and they kind of learn along the way. So by the time a young male becomes a dominant male, he has a pretty good run of the house or whatever the facility is, to know what to touch, what not to touch. And I’m sure there’s communication between the mice as far as, “Don’t eat this, don’t go near this, don’t run on this.” Except if there’s another dominant male who wants that territory, he might try to trick them.

What To Do When Mice Avoid Traps and Baits

John: Interesting. So say this happens now, you’ve tried everything, you’ve put out the snap traps and they’re avoiding that. You’ve put out glue traps, they’re avoiding those, maybe they’re nesting in the bait stations, like you said. What’s the next step in terms of catching these mice that aren’t following that expected behavior?

Zack: Yeah, I think exclusion is really crucial in this. In a single family house under 3,000, 5,000 square feet, a good size house up to that, or even a small house. We can do an exterior exclusion, prevent new mice from coming in, stop the flow of food from the outside to the inside, and then we can maybe try to control the competing food sources within the home. So if the dog food is being left out and the dog is free feeding, let’s just change the time feedings for a little bit. Let’s give the dog dinner when it’s dinner time, as soon as dog’s done, pick it up. Same with the cat food. Same with all the other competing food sources. Let’s not let the kids eat on the couch for a few weeks, see what happens.

So really kind of starve out the mice from their normal food and their normal behavior going in and out to give them no other choice but to try to eat either the bait or something on the snap trap. Interior exclusion, especially in multifamily homes, even just a two family or three family home, when we exclude mice from their normal paths of travel inside of an apartment, we’re really messing with their normal routine. It’s like if you’re driving from your house to work and maybe you have two or three routes that you could take, you usually take one, but sometimes you want a more rural view or sometimes this one it gets flooded when it rains. So you have a few different routes.

If we cut off all those three routes and we only leave you with the rickety bridge and you have to get out of your car and get into another vehicle to go over the bridge and walk the rest of the way, it makes you uncomfortable. It makes you a little bit dopey by the end because you don’t really know what you’re doing. So a lot of times when we do interior exclusion, we’re messing with the mice just enough to make them a little bit more willing to do something that they wouldn’t normally do because they have no other choice.

So those are situations we do have success with them changing their behavior just by closing off their pathways, doing that interior exclusion, removing clutter, removing a harborage area, making them very uncomfortable. If we can make them uncomfortable, we can start to manipulate their behavior.

Another key thing we can do is maybe treat the wall voids with a material called tracking powder. It’s a higher test material. You need a special license to use it. It’s a category 41, it’s a commercial license. It’s pretty high test stuff, so we’re pretty careful with it. We don’t use it very liberally because it’s toxic. If you think about a second generation anticoagulant is 0.0025% or so for most baits, 0.0025% active ingredient, that tells you that the active ingredient’s pretty active, but it’s a very small percentage. It’s just enough to kill a mouse.

But if you look at the tracking powder, it’s 0.2% of the active ingredient. It’s a first generation. It’s not as acute a kill, but it’s a lot more of that active ingredient in there, so we’re really careful with it. But treating wall voids, and then closing up those voids, that’s one way that we can eliminate the mice inside the walls and really change their behavior. A few of these really, really difficult cases, more in single family homes or two family home, we’ll put out night cameras, trail cams, and watch their behavior and see that every night they’re going from this room crossing the threshold to get to this area and then crawling up the stove.

So we’ll put out the cameras to find out what they’re doing, what their behavior is, and a few times the only thing we could do was say, “Dad, when did the kids go to bed, take these glue boards, line them so there’s not a half inch, not a quarter inch, not an eighth of an inch of paper showing, glue to glue, wall to wall on these thresholds.” One, two, three, these three thresholds. We know they walk every night and we’ll double wide so that mice, when they jump, it’s just a little bit too much glue board for them to jump on to. And sometimes that’s the only way we can do it is really just giving them no other option but try to jump that rickety bridge. And we know that rickety bridge is rigged up with pest control measures.

John: Right, so you’ve basically just blocked off their entire route and made it so that they absolutely have to go over that glue trap in order to get to where they’re going.

Zack: Right, right. Exactly.

John: Interesting. All right, well, that’s really great information, Zack. Thanks again for speaking with me today.

Zack: My pleasure.

John: And for more information, you can visit Colonial Pest Control’s website at colonialpest.com or call 1 (800) 525-8084. That’s 1 (800) 525-8084.