Best rat traps and rat prevention?
August 5, 2019 10:09 AM   Subscribe

The house immediately next door - feet away - is long abandoned and has a longtime critter infestation (rats, raccoons, etc.). But the house is being demolished. What can we do to reduce the rats relocating to our house? (No cats allowed.)

We heard from neighbors that they found a ton of rat traps on the abandoned property in the past. The critters seem to prefer the abandoned house to ours, although we occasionally see critters, but they leave our garden alone mostly. But we just got notice that demolition is starting soon and a bunch of poison rat traps appeared around the sides of the house. And other neighbors seem justifiably concerned about the critters relocating to our homes.

We leave our doors open during the day when we are home for air flow. Should we stop doing this?

What are the best humane rat traps? Do we care about being humane? Maybe we should use poison too? There aren't any neighborhood cats thankfully.

We have a ton of stuff growing in our garden and we're in an area with a late growing season, so we get produce well into September and October. I don't even know if cages would be worth it though.
posted by k8t to Home & Garden (14 answers total) 1 user marked this as a favorite
Response by poster: Also we are renters, so expensive permanent solutions are not at the top of our list. We also don't have direct communication with the new owners yet.
posted by k8t at 10:12 AM on August 5, 2019

Your garden is toast. The rats will eat from those existing poison traps and shit in your garden, and poison your soil and veggies. Unless you fully enclose your garden, including cages that go underground at least six inches to prevent burrowing, you should not expect something edible from there this year.

Poison is really the only way to get rid of the rats. "Humane" rat traps are hilariously ineffective at colonies. You have to check the trap every hour and remove the dead rat from the snap trap, electro-trap, or gas trap. Imagine doing this with hundreds of rats. Are you ready to be on 24-hour rat patrol?

If you want to prevent critters from taking up residence in your home, you should bring in an expert to assess the home. Since you're renting, your landlord needs to take this seriously and bring in someone NOW to seal up exterior areas to prevent rat infestation later.

Ugh, you have my sympathies. This happens a lot in my city and the rat problem explodes whenever there is construction. The neighborhood one over from us was in the news a few years ago because an abandoned building partially collapsed because the rat burrows underneath it were so deep that the building foundation fell in on itself.
posted by juniperesque at 10:50 AM on August 5, 2019 [4 favorites]

The most humane way is snap traps. Kill them quick, poison is a slow lingering death that
kills animals that might eat the bodies. You are doing them a kindness, if numbers are that high & their shelter is gone they'll die slow deaths to predators & the winter or the neighbours poison anyway. Other downside to poison is they'll die in your walls & stink out your house until they mummify. If squeamish, buy cheap traps & throw it all out trap & all. Rats are nocturnal so put them out in the evening, check in the morning. Keep doors & windows shut, specially on demolition days.

If you have a cat or dog watch them as they will catch the poisoned rats (they are easier to catch than healthy ones) and can ingest the poison.

Plug all holes into your house with steel wool or expanding foam. Make sure all food (including pet & bird) is in vermin proof containers. Your garden might well take a hit, cages as suggested might help. Make sure if you have mementos stored anywhere they are in vermin proof containers, and not say just shoved in cardboard boxes. My childhood memories did not survive a Australian rat plague one year when they found a lovely nesting site in the middle of the box.

Clear brush around back yard & house. Rats hate being out in the open. If it's only one houseful of rats & you make you your place unpleasant for them to be. No nesting spots, no easy food, open with no hiding spots. They should move onto easier locations. Good luck.
posted by wwax at 11:21 AM on August 5, 2019 [3 favorites]

Seconding snap traps. Use the larger rat version, not the smaller mouse version. Rats are wary of things that smell human, so wear gloves when you take off the plastic wrap, arm, and position the traps. Sticking dried fruit on the trigger gives them something to tug on, which positions them for a quick death. Rats like to hug walls, or wall-like things like fences, so placing traps there ups your odds.

Good luck!
posted by dws at 11:44 AM on August 5, 2019 [1 favorite]

When you say "humane" traps, do you mean traps that kill quickly or traps that catch the rat alive? You don't want to be thinking about catching rats and relocating them. Their preferred habitat is where people live so you'd either be passing your problem onto someone else or (if you found some very wild, uninhabited place to release them) letting them die by starvation or predation.

A long abandoned house is obviously not a great source of food, so once the house is demolished the rats are not going to be any more in need of food from your garden than they are now. They are going to be more in need of a place to live but if your property was great rat habitat a lot of rats would probably already have spread there from the house next door. So I'm guessing you're not going to see a huge impact from the demolition. Putting out traps and/or poison does seem like a good idea but I wouldn't panic.

I wouldn't worry too much about leaving your doors open. Rats are more likely to try to enter your house through small, unobserved cracks than to go in through the door. I wouldn't try putting cages around your garden plants. Rats can easily burrow in if they want to.

I did a little googling to try to find out whether any poison that gets into the soil of your garden could be absorbed by the plants. According to this paper, that can happen when warfarin bait is applied to soil where cereal crops are grown. But the largest concentration of warfarin found in grains in that study was .065 ppm. Page 22 of this long paper about warfarin shows that when rats were fed 1.5 ppm daily for 40 days only half of them died. So it doesn't seem likely that rat poison that gets into your soil from rat poop would make your garden vegetables dangerous for you to eat.
posted by Redstart at 11:59 AM on August 5, 2019 [5 favorites]

You do want to close off any entry to the house - focus first on holes in siding, broken attic vents, etc, but yes they absolutely will run in an open door if they want, especially if they feel too vulnerable outside. Clear out any accumulated leaves or yard debris (especially under/behind shrubbery) they might feel comfortable in, and if you have compost that isn't in a closeable bin or tumbler. I think it would take more direct application of poison to damage your soil; even the crappy rodenticide disrupts their digestive cycle pretty quickly, they stop eating and pooping, and they're not really passing it at that point.

As problematic as poison is, it's clearly already being put out and hopefully it is the pro stuff that works pretty fast and they won't travel far. You WILL get some dying rats on your property, and you should patrol for them (in a similar situation I used a rake-and-bin poop scoop set which will contain a sick-not-dead rat long enough to get to the trash bin) to remove them before wildlife or natural consequences get involved. You should patrol at dawn and dusk for sure (with a flashlight), but if you can do another sweep in bright daylight it can be easier to find them.

Poisoned rats that are still mobile, and healthy rats in hot weather, will be drawn to water. If you have a birdbath or drippy spot under a hose bib, or leaky sprinkler or something, you'll want to get that situation resolved and keep it dry for a bit. They'll go after even wet cardboard or damp garden soil, so if you are accustomed to watering your garden in the cooler parts of the day you may want to stop that for a week or two and water at midday or early late-afternoon while there's still some hours of sunlight ahead.

I too wanted humane solutions, but they are limited in efficacy. Rats are smarter than mice, by a lot, and they're also super suspicious of new things, and they'll exhaust any other easier food source before they'll brave the baited traps.

And...snap traps don't always work as intended. It can be really fucking gruesome, and they don't always die*. Getting them to go into a live trap is, again, hard because they are suspicious, and then you have to do something with them. I used a couple of ratzappers, and had more success on average than live traps (probably because the design is such that you can put a LOT of compelling food in it and they can't steal it without crossing the contact plates). I got a lot of adolescent rats with that one, which might be that they are less attenuated to danger or something.

You can try to put traps out in a wildlife-friendly way outside (consider cardboard boxes with a pretty small entry a squirrel probably can't get in, or put them out only at night under milk crate or laundry baskets), but I would focus as much energy as possible on closing up access or discouraging movement around the outside of your home so they don't get in - motion-sensor lights low to the ground and up at the gutter-line if you can, get a couple plastic predators and move them around every day to keep them fresh, keep the doors closed for a while. I would sit outside the day of demo, and through that evening, and watch for movement to see if they're coming around. Do spot checks (sit outside relatively still and quiet, and listen and watch) every night for a week. Scare them off physically if you are seeing movement - beat the bushes with a broom, smack the roof/gutter with a bamboo pole or broom handle, patrol with a bright flashlight pointing it into hidey holes.

*If you're going to use any kill traps, you'll want to have a household discussion about management and disposal, including if something goes poorly. I am mostly not a squeamish person, and our rat adventure last year changed me some, but a few times things happened that I just Could Not Deal With and that was okay when my husband was home because he is willing to deal with them, but then things happened when he was not there and it was bad and I had to do it. Also, you have to check your traps every day, all the traps, don't forget about one, make a list of where they are.
posted by Lyn Never at 12:12 PM on August 5, 2019 [1 favorite]

According to this paper, that can happen when warfarin bait is applied to soil where cereal crops are grown. But the largest concentration of warfarin found in grains in that study was .065 ppm.

Just to put some context on these numbers, warfarin, the most common rat poison, is actually used as an anti-coagulant drug in humans. It comes in 1 and 2 mg tablets. In order to get the equivalent dose to a 2mg tablet, you would need to eat about 30kg (or about 66 pounds) of those tainted grains. One of the reasons warfarin is used over older types of poison is that it's less likely to make humans and other animals sick from environmental exposure. (But if you have cats or dogs, you'll definitely want to make sure they're not eating any potentially poisoned rats.)
posted by firechicago at 12:39 PM on August 5, 2019 [3 favorites]

I’ve gotten mice from having a door blow open while I was out of the house. There’s no way I would take a chance on leaving the doors open as long as there were homeless rats nearby looking for a place to stay.
posted by corey flood at 12:49 PM on August 5, 2019 [3 favorites]

Close the doors, immediately. Check your walls and vents for nooks and crannies they might squeeze through, and seal up any such gaps. Don’t leave food out in the house, and don’t put food out (either scattered or in feeders) for birds. Make sure your rubbish bins have tightly-fitting lids, and that all refuse goes in rubbish bags inside them - avoid leaving food scraps around the bins.

(Ignore any advice that recommends peppermint as a natural rat repellent; our pet rats would scoff an entire tube of toothpaste each if we let them.)

If you do decide that you have no option but terminal pest control* please do consider electrical shock traps rather than poison (the latter is horrifically inhumane and causes a great deal of suffering, not only to rats but other wild animals). Good shock traps are also more reliable in causing a quick death than snap traps.

* Not judging, I promise. I’m admittedly soft about wild rats myself, and can personally coexist with them nearby [and have done!], but I appreciate that others feel differently.
posted by Morfil Ffyrnig at 1:20 PM on August 5, 2019

as others said, you're going to need to seal off every little crack, every little spot offering ingress to the home (especially to the attic and crawlspace.) It's a non-intuitive job and a professional may be the way to go. I was shocked at what they pros I hired found.
posted by fingersandtoes at 2:15 PM on August 5, 2019

I've heard, anecdotally, that coyote urine actually works to repel them. You can buy it online.
posted by fingersandtoes at 2:16 PM on August 5, 2019

Suggestion on the snap traps - yes, dried fruit. even crisp fresh apple works. If the bait doesn't hang together well enough to set off the trigger, you are just feeding them.
And yes, sometimes the trap doesn't kill immediately. What I did was put trap, rat and all in a plastic grocery bag, try to squeeze out as much air as possible, then fill the bag with car exhaust. Carbon monoxide.
posted by rudd135 at 5:30 PM on August 5, 2019

I'd just get rid of anything edible in your yard. Sorry, I know it sucks, but it's only for this year. So harvest early and take the rest down. Next, I'd see if your landlord would spring for a rat proofer to come to your home to do an assessment and shore up any holes. Keep your doors closed, of course. I'd move items in the pantry into containers that can't easily be accessed. If you hear anything in the walls or ceiling immediately call an exterminator - that day!

And last, and this is not to freak you out, but start putting the toilet seat down. They can get into the plumbing and pop up in all sorts of unexpected places.
posted by Toddles at 12:01 AM on August 6, 2019

You should seal your place as much as possible, but I doubt you're going to have as big a problem as you fear. Before freaking out and DEFINITELY before using poison, wait and see what happens. I wouldn't assume that the presence of traps means that there are a vast number of rats over there (some places, like Seattle I believe, actually mandate traps to be set around buildings being demolished) and I suspect that you won't find a major increase in rats on your property. (Probably a decrease because of the poisoning that's already occurring.)
posted by metasarah at 10:01 AM on August 7, 2019

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