Mice consuming a lot of bait

I have two mouse infestations - in the garage and the attic. I've used Just One Bite II bars in the past with success. So far this season I've gone through 1 bar or 1 pound of bait (which is more than I've used in two seasons) in about 10 days and I'm still not done. The packaging states mice may consume a lethal dose in a single night's feeding. Mice eat 4-5 grams a day (453 grams in a pound) so that would mean I've had 100 feedings or 100 mice and am not done yet. This seems incredible, particularly as I haven't seen dead mice from the bait, heard or smelled anything.

I'm satisfied the issue is mice, not something else as I've trapped a few and I know the poop. Also, I know mice may stash food so the numbers may not correlate exactly but I feel I'm missing something. Any thoughts?

 

Poisonings mice is not a great option, they die in places that can then cause smell issues, or die and other animals eat.

Trapping is the more humane solution.

Also I have seen many ads for the bucket traps, basically a large plastic pail with a swinging trap door that looks like a method to catch large numbers of vermin.

 

Is it possible some of your bait is being carried off instead of eaten in place?

 

Pilot Dane, yes that's possible as I stated in my OP. However, the bait has a hole through the center. I drop the bait around the hole. So, the bait is gone and the nail remains. But, they can eat some and carry away the remainder.

 

I've heard that bait is less effective if mice don't have a good source of water.
Both of my sons utilize the bucket of water and stick with peanut butter on the end/underside. I always use snap traps.

 

I hadn't heard of the One Bite II bars, so I looked it up, and it has a very good active ingredient; no problem with that.
Typically, mice don't stash bait block chewings. Good thinking to place them over a vertical nail as a holder. Pellets and sometimes the meal baits are the worst for getting stashed away. Rats and squirrels will stash bait blocks, but the nail holder would prevent that, and you're monitoring the bait placement well enough to know that you don't have larger animals.
Slugs will eat the bait blocks too, without any seeming toxic reaction. That could explain the garage, but probably not the attic. The pest control industry is plagued with slugs eating rodenticide. The larger species of cockroaches will eat the bait, too, and they have a mouse like dropping. I can't help but think that you'd know if you had that large of a roach problem. Crickets and grasshoppers eat it too.

Just because a mouse consumes a lethal dose doesn't mean it will stop at that. I didn't see any "stop feed" additive, though I didn't read everything. You may simply have a larger infestation than in past years. Keep plenty of bait fresh and available. It's a good rodenticide. I think that just a little more time will solve this. Keep us posted.

 

You'd be surprised at the size of rodent litters- Years ago, our neighbors horse died in a lightning strike; when they closed their stable, we got an avalanche of displaced mice and rats.
IF you have one mouse litter that has lots of females, when they grow and are in heat you will get every bachelor mouse in the area coming by.

 

I want to circle back on this thread. I've gone through 1 1/2 pounds of bait and several mice caught in traps. Today, for the first time (in 3 weeks) I've had 3 days in a row of no activity. While it's obvious we've had a lot of mice, I think there's more going on. I'm reminded of a guy bailing water in a leaky rowboat wondering why the boat is sinking and I think that's been our situation.

I did my final leaf blowing this morning and noticed a mouse running along the foundation. That happened a few times this year but I never saw it earlier. Now, I'm convinced my mouse problem included not just mice in the house but those nearby who came and went, as well. In the spring I'll mouseproof the house and, for now, I'll set bait stations outside. Up to now, I was reluctant to do so because I didn't want to kill other animals but I don't think I have an option.

 

Sounds like a good diagnosis and plan! There are bait stations made for exterior use, more expensive but they will keep larger animals out, but not so much squirrels, chipmunks, etc. I too think you should do it as something unusual is going on at your property. You don't have to keep the bait stations maintained year round necessarily as this degree of infestation may not happen again. Another thing you can do is to buy exterior grade stations that have room for snap traps inside and forgo the bait after the initial baiting, maybe.

https://www.domyown.com/animal-pest-...-321_1261.html

The copper mesh "Stuff-it", Pur Black, and Excluder strips are used and generally liked by those who do rodent exclusion.

 

My quick solution "pet proof" mousetraps is to put the mousetrap INSIDE an open cardboard box-
either cereal box, or the square-ish boxes that soda comes in.

This avoids the pet-sitting drama associated with guest pet thinking-
"Oh, they KNOW I like peanut butter and put some on a coaster. Wonder what that spring thing does?"

This ALSO works outdoors, mousetrap in the back of a breakfast cereal box.
Trick is, crush the box a little and put the box inside the plastic bag that holds the cereal.

 

I haven't posted since December, and this is an update to let everyone know how things are going. To be brief, improved but far from over. We continue to have mice, most recently a dead mouse in the garage and twice dead mice in the washing machine drum in the adjoining mud room. That makes three in the drum, overall. I believe there may be a nest inside the washing machine, but I didn't want to disturb them because I was concerned they might scatter so I used bait and traps.

I started to seal possible entry points earlier this week and suspect I closed an entry point as mice tried to create a hole in the door and created a hole in the wall at the dryer vent. This is the area I sealed.

So far, I found approx. 15 dead mice all in the garage, mud room and attic. We have not seen any live mice (except outside) and no droppings or activity in the living area, or basement. Most were poisoned and some in snap traps, none in glue traps.

All of the house mice seem to have been eradicated. The recent mice have been field mice, either deer or white footed mice. I thought the field mice had moved outdoors which is why I thought it was safe to begin sealing.

On the poison, I used one first generation poison, diphacinone, and switched off between 3 others: diphethialone, brodifacoum, and bromadiolone. Overall, I've gone through approx. 10 pounds of bait including the stuff I picked up because it may have become stale.

I believe the problem will continue until I finish sealing. Depending on the issue I'm using either concrete patch, expanding foam, or copper mesh.

 

Sounds like you are doing good work; I'm amazed at the amount of re-infestation. I thought the indoor problem would be gone by now. At this point, I too, would be sealing the exterior as best I could and trust the traps and bait to catch the ones trapped inside.

One thing we didn't talk about is outbuildings, wood piles, stored materials, animal pens/stables/barns. Do any of these exist within sight of your house? There must be a larger source somewhere nearby, and you're getting the overflow. If so, this larger source needs to be addressed sometime/somehow.

Here is an example of a multi-catch trap that may be helpful indoors. The mice will be alive, and you'll have to deal with them that way, so be aware. JT Eaton makes one, too, called the Little Pete. Don't buy the wind-up kind. The springs go bad or get overwound easily. If you use them and catch mice, don't clean them unless necessary, as other mice will be attracted to the mouse odors.
https://www.domyown.com/catchmaster-...rap-p-467.html

 

PA, it became clear mice continued to get in and was compounded by my inability to eradicate the nest. The field mice have all been found within 15 feet and I feel reasonably certain I've identified their entry point assuming it's close to where I found them - a vinyl siding outside corner post. I understand this is a favorite rodent entry point and all of my posts are open at the bottom. I'll be sealing all of them with copper mesh.

We don't have any buildings, livestock or anything like that near our home. However, our property slopes and we have a series of 4' high railroad tie retaining walls and steps, overall approx. 40' within a few yards of our mud room door. This is where the field mice were found.

 

I can report that I finally eradicated our mice issue, 4 months after starting. I went through over 10 pounds of bait and many traps in the process. Some of the bait was removed because it was stale, but I feel certain most of the bait was consumed. It became obvious some of the bait was more effective than others. From a combination of research I found and experience from my problem, I want to share what I learned relative to bait.

The key to my findings is that mice consume 3-6 grams a day, on average 4.5 grams. Baits requiring over 4.5 average grams will thus require multiple feedings. In addition, baits requiring only 4.5 average grams may also require multiple feedings if an alternative food source is available. Given that mice may store food or may have multiple sources, this is critical. All in all, it seems logical that the lower the amount of bait needed to kill a mouse, the more effective the bait is likely to be. This is borne out in research and in my experience.

I used four baits for a majority of my effort: diphacinone, difethialone, brodifacoum, and bromadiolone and one additional bait in the past month: bromethalin. Most of the time I used several baits at the same time and I believe this added to my problem because it gave the mice multiple choices so mice may not have had a sufficient dose of any one bait.

The University of Nebraska - Lincoln published helpful information on bait consumption needed to kill, as follows:
diphacinone: 11.1 grams, difethialone: 9.2 grams, brodifacoum: 8.6 grams, bromadiolone: 9.8 grams, and bromethalin: 2.3 grams. Bromethalin required much less consumption - 21-27% of the consumption of other baits. The study also found bromethalin, brodifacoum difethialone to be the only baits to kill 80% of mice within 3 days. No other baits had over a 20% kill rate.

My findings were consistent with this study. It wasn't until I switched to bromethaln that I could see results quickly, a few days. I found research that demonstrated two additional benefits to bromethalin. Mice stop consuming bait soon after a lethal dose so less bait will be needed. Also, since mice don't consume much bait secondary poisoning of larger animals is not an issue. In the future I'll be going to bromethalin first if I have a problem.

University of Nebraska - Lincoln study

 

Good work in all respects, Tony!

I would simply add, for future use, that all but Bromethalin are anticoagulants. Bromethalin is considered safer with respect to secondary poisoning, and you did point that out. I believe that Bromethalin is still used in California, a state which recently clamped down hard on anti-coags due to secondary poisoning in raptors. No sure of the details yet of their regulations yet.

Of the anti-coags, Diphacinone is the older, 1st generation anti-coag as opposed to the others being 2nd generation. 1st gen require multiple feeding. Cross feeding between different anti-coags would not hinder the toxicity at all. All but Diphacinone are single-fee rodenticides. Either there were a LOT of mice, or non targets such as opossums were getting it, or the rodents were getting vitamin k foods such as vegetables on a regular basis (rarely happens, but can).

Thanks for keeping us posted!

 

Good job solving the problem. If it hadn't been solved, I was about to chime in with "don't kill 'em, trap 'em and sell 'em to this guy."



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