Rodent bait causes other animals to suffer needlessly

I used to have mice in my chicken coop. Wilson has corrected that.

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Our cat is a terrific hunter - outdoors. He’s always leaving remains of voles, moles, frogs on the doormat.
But indoors, he seems to have no interest whatsoever in the field mice that moved in and were stealing/stashing his dry cat food (and my pecans) everywhere around the house… they especially seem to like shoes.

Traps and Vit.D3 rodenticide baits have knocked the indoor population back, and moving the cat food out of the laundry room probably helped just about as much… but that moved them to concentrate more on my pecans.

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now outside my small dog gets the mice. in the house the cat gets every mouse. our new big dog hates squirrels so that’s good.

in the greenhouse and hoophouse the mice go wild though. I won’t use poisons because I like my predators so I’ve tried that mouse x stuff that supposedly dehydrates them (doesn’t work) then ended up buying two electric chair boxes that zap them when they go inside.

CD those seemed to do the trick, I caught about 6 mice, small fellas and the traps have turned up empty since then. the damn things were eating all the melon and squash seeds I was putting in to start! plus they got into the only unsecured bag of grain, hulless oats, that I had. no oats for me this year I’m at my garden budget and so it’ll have to wait until next

the zap traps are great. humane and you just throw on the garden glove, open, toss the mouse (I throw them in the “not quite compost/waste” area) then turn the switch back on. the batteries last a long time and are rechargeable.

I lived out in the woods a while and hated seeing animals that got that second hand dose from dead rodents. even the wild turkey weren’t safe from it, one day I saw a lil flock of them eating a dead mouse or rat in the field by my neighbors house, two days later there were three dead wild turkeys that could have been my dinner, but instead were dead in the woods. shudder to think of the vultures and wild cat and other scavengers that might have got some

Most modern rodent poison baits that individuals are allowed to buy without licensing or regulation in countries like the US are not deadly to animals that eat the poisoned rodents. Many require considerable ingestion of the poison itself to kill and anyone who keeps it properly contained should not create an issue. That’s not to say illegal use of regulated poisons and just tossing whole blocks of the stuff around doesn’t happen. One of my dogs has eaten nearly an entire block of bromethalin containing poison twice now because my mom just tosses it under a desk in her office in nothing. It’s not even a rodent attracting location, I’m not sure she’s seen a mouse since we quit keeping horses in the stable at her house, and none of the blocks ever have chew marks when she thinks to remove them before I bring my dogs over or my sister shows up with her little corgi and 1 year old child. Luckily it would take a few dozen blocks to cause my dog definite harm. A block gives her a slightly upset stomach for a few hours and so far no further symptoms. My sister’s corgi could potentially be affected and I’m not sure what would happen if my sister’s 1 year old child got a hold of it.

In my own house I tried quite literally everything to keep non-native house mice out of an 1800s farmhouse that had become part of a crowded city neighborhood with lots of cheap rental houses. There was no way to block up every gap in that house. I was only half joking when I told my mom the walls of that house probably have more mouse poop than insulation in them.

I put out boxes and boxes of flavored plaster and other homemade bait suggestions that posed little threat to other animals but I couldn’t keep up with how fast they multiplied. I emptied traps several times a day and couldn’t slow them down. The only food they could get to was the dog kibble sitting out in the bowl and that would mean crossing the room with 4 dogs in it whenever they weren’t outside and often 2 cats and 2 humans during the day. Yet they still kept increasing. I sprayed deterrents that weren’t toxic to larger mammals all over and they kept increasing. They destroyed registration papers and health records for the dogs and cats, pedigrees for our chinchilla breeding group, and we will probably never know what all else. I cleaned up so much mouse poop and pee and kept disinfecting things.

Then the mice became infested with mites. I started spreading DE first and moved on to sevin dust in the house. I treated every pet rodent plus dogs and cats repeatedly with topical mite and flea meds. Some gerbils went into seizures from the amount of mites biting them and cleaning even a cage I’d moved gerbils out of and let empty for a week would have rat mites crawling up my arms. They started coming out of the bumps on my skin whenever I got wet or spread lotion. I went to a doctor thinking it might be scabies before we identified the mites. Not applying anything to my skin the mites did not appear and he claimed it was allergies without doing any testing. I should have used the sink in the room or something to make them crawl out. The mites were living in me and I think my brain has partially blocked the whole situation from memory or maybe I suffering such horrible inflammation and brain fog I couldn’t remember everything we went through and how long it went on. I got so desperate I spread DE across the bed and slept in it.

Enough with poison avoidance! I got some secured containers and a whole bucket of the latest rodenticide from the feed store. I placed the containers where dog heads couldn’t fit so it was extremely unlikely they’d even manage to get a sealed container to chew open. The mice steadily disappeared. The mites did not. Phorid flies appeared.

I kept spraying and spreading powders and cleaning and sealing away all food, garbage, etc… I put more chemicals on myself, the pets, the floors, down the drains, and I couldn’t get rid of the secondary pests brought by the mice. We had reptiles and there is a recent trend of using predatory mites to eat pest mites because reptiles do not handle treatments for snake mites well. I found greenhouses frequently used predatory mites for fungus gnats and other soil dwelling pests so I ordered the cheapest quantity I could find. A little container of dirt arrived with no obvious life in it. I set out a seedling tray on the floor of the room with our gerbils and guinea pigs in it, added a layer of dampened plain top soil and spread what seemed like a very expensive half cup or less of soil on it.

A few days later the mites were no longer coating my arms and weren’t visible on every cage surface. A little group of darker, smaller mites appeared by a sink and the bathtub once. They were only noticeable when grouped on a smooth, light colored surface so there’s no way to estimate how many predatory mites spread through our house. Considering the 1,000s or 10,000s of reddish mites roaming around we had apparently unleashed a ravenous army of mostly invisible mites. Within less than 2 weeks they had stripped all 3 stories of the old, drafty farmhouse with hollow plaster coated walls of every last large, red mite that I had spent months trying to kill without excessively poisoning ourselves and our pets.

The phorid flies took another year to finally get rid of since they can create a new already flying generation within 24hrs on the slightest food residue. Fans, geraniol oil sprays, and traps kept the numbers down until we finally accomplished cleaning all drains thoroughly and removal of all food sources for 2 weeks straight until they all starved or were killed.

When the mice and mites were gone I gave up on trying to scrub some things clean even with a strong hospital and veterinary disinfectant. I decided to strip and resealed hardwood furniture like our antique dressers. We ripped out the kitchen cupboards and put in covered utility shelving units because we couldn’t afford to replace them at the time. It took longer to clean up the mess of stuff I’d spread around and mouse waste than it did to get rid of the mice with rodenticides.

For the next 8 years until we moved I never ever let the rat bait run out in the containers behind the fridge, the bathroom cabinet, and other places the dogs could not reach them. In the past on a farm we had lots of quail and some chicks killed by rats because we tried to avoid using poison baits. We had enough foxes, hawks, and so forth they never truly got out of control like they did in town but they did kill many small poultry and a few litters of rabbits.

When the rodents started appearing at our new house I insisted on identifying every one possible even if half eaten by a cat to determine if it was native or the invasive species of house mice and rats that will take over if you give them the slightest chance. Natives will show up for awhile in bad weather or low food seasons but usually don’t take much to deter from hanging around and reproducing. They have always chosen to leave any building with human or larger mammal traffic without needing much encouragement. All of our rodents at this house so far have appeared to be native woodland/meadow/field mice, voles, and shrews so we didn’t put out poison bait. What few insisted on trying to winter in our house or under the deck were wiped out by dogs and cats.

If non-native house mice or rats are multiplying out of control use poison. Don’t mess around and think if you just keep applying alternatives, locking up food and garbage, and cleaning things they will go away. The rodents will bring other pests and diseases with them that could kill your animals or even you far more effectively than modern rodenticides placed in an appropriate dispenser. Non-native species of mice and rats are damaging to the environment as well.

This is a situation created by humans and most commonly in the US and some other countries non-native species. Predators are not enough to undo the results of human provided shelter and food sources. It does sometimes require human intervention to make up for our actions creating the excessive rodent population and further contributions from having reduced or in some places nearly eliminated most useful predators. Use the products designed to kill the harmful rodents responsibly and it can be beneficial to the health of most things around you compared to a massive rodent explosion.

It’s those people that don’t follow regulations or instructions on the packages and countries that don’t have strict enough regulations or access to safer poison baits that cause the death of non target species and environmental damage. Use the correct product in the necessary quantity and properly contain it.

Whatever you do don’t toss the freaking poison straight on the floor or outside on the ground where anything and anyone can come in contact with it!

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That’s quite a story. I’ll probably have nightmares now. But thanks for sharing it.

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Whoa. Thanks for sharing your story and welcome to the forum. I hope you never have to deal with that again.

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I lost a Welsh corgi who got into rat poison. We got her to the vet within 24 hours but he said the vitamin k was given too late to reverse it.

Whatever you do don’t toss the freaking poison straight on the floor or outside on the ground where anything and anyone can come in contact with it!

I absolutely agree! It’s possible it has been reformulated since my loss but who is willing to take the risk?

d-dbriefoct2002.pdf (226.9 KB)

Welcome to the forum, and dang! That is quite a story.

Many places are attempting to further restrict anticoagulant poisons. The one my mom keeps leaving out is a nerve toxin. There is no antidote if something does ingest too much besides inducing vomiting and trying to use activated charcoal to absorb it but it takes a whole lot more to impact other animals.

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I’m trying this approach to control pine voles in my nursery - has anyone done something similar? This was shared with me by a grape-grower who had their entire planting decimated by voles, and this seemed to work. I’m planning to place traps outside of tunnel entrances, perhaps with a large box covering them to prevent any other animals to get to the bait.


You can eliminate ground squirrels and rodents without harmful poisons by using a bait of one
part plaster of paris to three parts raw oatmeal and placing about a cup at a time in the upright
tube of this simple Rodent Bait Module built out of PVC pipe. The mixture constipates and kills
squirrels and other rodents, but has no harmful effect on predators that may eat the dead animals.
The traps have been used for years by wildlife biologists in California and other areas. Some
designs use an upside down T made out of 4-in. PVC. This design includes a 30-degree angle
fitting to keep the bait inside and to protect non-target species. The trap can be buried in the
ground (or in feed lots or feed storage areas for other rodents) with only the openings exposed.
Caps can be screwed on the ends when rain is expected to protect the bait from getting wet.

Plan:
As I mentioned, we will use oats and plaster of Paris.

  1.   First we will fill the bait stations with oats ONLY.
    
  2.   Second after a week a good feeding, we will add the plaster.
    
  3.   The stations will be in PVC in shape of a upside down T with a cap on top so that
    

the bait remains dry, is only accessible to ground squirrels and will be easy to monitor
for bait depletion.
We will use a total of 8 stations in our fields.

  1. Add oatmeal, plaster and sugar or chocolate powder as 1:1:1/2 ratio into a bowl
    and mix it well.
  2. Then, place 1 or 2 cups per bait station.
  3. Check level of bait daily.
  4. Refill station as necessary.

Years ago, I used - and advocated for - peanut butter/Plaster of Paris ‘bonbons’ as a tree rat ‘poison’. I had placed those little pb/PoP balls where they were readily accessible to squirrels. Pilfering seemed to abate significantly, but I never saw any dead or distressed critters.

Seems like someone in this group live-trapped a squirrel and fed it pb/PoP exclusively for a couple of weeks…with no ill effects noted. Kinda burst my bubble…

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Yeah, that was me who fed a squirrel Plaster of Paris mixed with peanut butter. It was 50/50 mix.

The experiment was rightly criticized for only having a sample size of one (and one control squirrel I fed acorns) but it was more than anyone else had done. The squirrel seemed to have no problem digesting the plaster of Paris. It did slowly turn the squirrel’s poop white as the plaster of Paris worked through his digestive tract, but never killed it. I think I fed it the Plaster of Paris concoction for about 2 weeks and gave up. I kept both squirrels in two large separate dog cages. I took pictures and recorded the whole thing on internet. It’s been over 10 years ago.

I did the experiment because there were a lot of people using the plaster of Paris for squirrel control, but no one could confirm that they saw any dead squirrels, from the bait (as Lucky mentioned above). So there was a sort of debate among backyard fruit growers whether the Plaster of Paris worked or not.

There were some people reporting on fruit forums that were feeding purchased rat bait (I don’t know if they were using anticoagulants or bromethalin) to squirrels and they were seeing dead squirrels, so I, and others, wondered why no one was seeing dead squirrels from Plaster of Paris. I tried to offer some small amount of testing to have any any idea if it worked or not.

It is possible to die from bowel/stomach obstructions. Below is a case study where a woman tried to commit suicide by eating 450g (1 lb.) of straight/undiluted Plaster of Paris. It caused a digestive blockage. I’m of course not a physician, but I would guess she would have most certainly died had the blockage not been surgically removed. Probably a very long painful death. I used to be a pig farmer, and pigs are sometimes born with a “blind anus”, meaning they have no anus. They will live a surprising amount of time before they eventually bloat up and die. Of course once these pigs are identified, we would euthanize them to spare them the painful death.

It’s possible that my squirrel sample of one didn’t eat enough at one time, or that mixing with oats would somehow be more prone to cause a blockage, but I’d be skeptical that it caused a blockage, unless there was also visual confirmation of dead squirrels, preferably with some postmortem examinations of the stomachs to confirm blockage.

I know personally of one other backyard orchardist who had so many squirrels pilfering his fruits, he was getting no fruit from his fruit trees. He put out zinc phosphide bait and said he saw dead squirrels everywhere the next day His experience matches others that I had read on the internet. Namely that known lethal bait results in a visual confirmation of dead squirrels.

Still it’s possible Plaster of Paris and oats kills the squirrels so slowly from blockage, that they run away to die? But, I would have to see some controlled experimental confirmation (on a large sample size) before I’d believe it. Such a large sample size would be beyond my resources (or interest) so I won’t be doing any more Plaster of Paris experiments on rodents.

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A few years ago we had a late freeze and we kept on finding dead squirrels in our yard. We found out that an unexpected frost can end up killing them as they cannot retrace their steps and that squirrels are very territorial. At first we thought the squirrels chasing each other was them playing but we learned that was them chasing the other squirrel out of its territory. Since they are territorial new ones often just replace the old ones kind of like rulers taking over kingdoms. We use the dehydrating mouse traps for things like squirrels and bunnies but try to not put them in open areas.

I’ve tried a lot of vole deterrents, traps, and other, to no avail.

We’ve had some success with this thing

I’ve also read that dry ice can work.

Dry ice works; if you happen to have a CO2 canister from home brewing or welding that works too.

Plaster of paris works on small numbers of rodents attracted to the chosen bait if refreshed often enough and they don’t have plenty else to eat that will counter the amount of plaster. Especially watery or stool softening foods, which fruit generally counts as. If they prefer to eat a ton of currently growing fruit or lots of new green shoots over eating the plaster it isn’t likely to work well. If mostly all they have is high fiber older plant matter, seeds, nuts, some harvested grains, etc… and reason to eat enough plaster bait it will kill some. Whether it kills them fast enough to eliminate the problem depends on the starting population, any sources for more rodents nearby, and species.

When we used it for the mass of house and shed dwelling non-native house mice it only slightly slowed them down. We started putting it out in late fall with the only food on our property being a few apple trees and berry plants that the birds had finished cleaning up whatever we hadn’t picked. The mice were coming inside due to the lack of enough food anywhere else before it got all that cold and we only noticed a few signs of them then. Despite being the only food source on our property though it did not work for such a rapidly reproducing species of rodent with no predators around. I think I went through 3 boxes of plaster with some mixed with peanut butter, some mixed with grains and other ideas people had that I don’t remember all of before giving up on it completely. It’s not like they weren’t eating it. They were just multiplying fast enough on I have no idea what for other foods that it didn’t kill more adults than the offspring they managed to raise.

For voles that both reproduce and move slower I’ve never had to do much except not chase off every possible predator and let the dogs sniff around where they are hiding. It worked on 42 and 80 acre farms. The latter having large trellises of hundred year old grapevines, blackberry bushes gone wild in a 10’ wide by about 200-300’ long area between where the grass was mowed and a creek bed, and lots of older, heavily producing nut trees. Rodents except invasive rat species were still easy to control with predators.

The dogs also completely stripped our new yard in a small town of all the native voles and shrews in the first summer all by themselves after the previous owners spent years trying to deter or poison the rodents without managing to get rid of them. The amount of rodent digging had them thinking there was a mole problem but there were no large mounds in the middle of the yard. Dozens of dead shrews and voles kept appearing though with increasingly fewer being younger ones.

For places you can let them roam chickens have to be the most efficient, least damaging, small rodent control (as well as some insect pests) I’ve ever had. My husband who grew up in town found it quite surprising the first time I told him to just go empty the live trap in the middle of the chicken flock. The whole flock went nuts fighting to get the mice and gulped them right down without a single one getting away. Very few things smaller than a rat will survive even a flock of most bantams left to wander the area. Japanese bantams were designed to be essentially living garden decorations so disturb soil and plants far less than most poultry, are not easily startled, and make very little noise. Aside from being the only ones I let around new plants and herb garden beds I even had a trio with a rooster in the spare bedroom on the other side of the wall from where I slept for some fresh winter eggs with hardly enough noise to let anyone know they were there. Too bad even the tiny bantam breeds aren’t allowed in any city limits I’ve lived in since then.

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I’m curious, did you ever see large numbers of bodies of dead rodents immediately after setting out the Plaster of Paris (that you were certain were not caused by dogs or cats?)

There were some dead mice in the small plastic containers I used to contain the plaster so the dogs were less likely to accomplish eating any. I cut holes a mouse would easily fit through in the side and there is no way they simply got stuck. I don’t remember how many were in the bait containers but when refilling them I’d have to dump some bodies. There were also some dead in the basement and occasional smell in some rooms from likely dead mice in walls or between floors. The phorid flies that appeared most often get established as indoor pests due to dead animals under homes or in attics.

Nearly all dead mice found prior to putting out rodenticide were plaster baits or natural causes besides predation. I don’t know how many that was partially because the mice soon seemed endless in numbers. More than should have if we did nothing definitely died but at a slower rate than they made more or we gained more from where ever they started coming from.

Our cats at that time were useless. They accomplished one dead mouse and I’m not sure they killed it. The one we still have we bottle raised and the other cat at the time had been indoor only from 3 months old. While my family had a rat terrier mix on the farm my dogs have all been 50lbs minimum so in a house they can’t get rodents before they dash under furniture or behind things. Probably only 3-5 mice died to dogs indoors. If you want a yard or field stripped of rodents and don’t care about the holes that dogs up to 120lbs can dig they will spend all day and night obsessing about the rodents until they get to them. Indoors they just knock things over and stare under furniture insisting you get the mouse out for them.

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Thank you. This is the first time I’ve ever heard anyone see dead rodents from Plaster of Paris.

Would you mind giving the formula of proportion of food and Plaster of Paris?

If Plaster of Paris truly kills rodents, then that would be quite helpful for me. We have voles that can be very damaging at our orchard we poison with zinc phosphide. It’s expensive and can be dangerous to handle. I would much rather use a safer and cheaper product, if it works. Baiting occurs during the winter, so the voles have no source of fruit or green vegetation, only seeds.

Even though I said I’d never do any more testing, I may try to test it first to see if it works, so I’m not putting out a benign product.

I have a friend who is a mouse farmer (yes there is such a thing). As I recall, he raises over 1000 mice per week, for pet food stores. I may try to get him to run an experiment and feed a few mice the Plaster of Paris concoction. That’s why I need the formula for exact ratio of food to Plaster of Paris. I know he’s not going to want to tinker around and do the experiment over and over to find what works. Since you already have the secret sauce, I just need to know the formula.

If Plaster of Paris really works, it would be an enormous breakthrough, not only for me, but for others as well.

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