How I Got Roof Rats, How You Can Avoid Them and Why You Should.
*Advisory: This post contains links to graphic images of dead roof rats. If you would prefer not to view them, please refrain from selecting the links, which I’ve clearly marked for everyone’s comfort*
Roof rats are extremely common out here in the west. Or as they’re also called… fruit rats, citrus rats, palm rats, black rats, ship rats and if you want to get sciencey about it… Rattus Rattus. Whatever you call them, they’re dirty, disease spreading rodents that can wreak serious havoc on houses, cars and gardens. Up until a few months ago, I had absolutely no idea they even existed. Consider me now thoroughly educated, lol! By necessity, I’ve learned more than I ever wanted to know about the species!
Most things have come to a temporary halt on the homestead to deal with them. Though the saga is not quite over for me, I’ve learned a lot about what works, what doesn’t and measures I COULD have taken to prevent them. Please benefit from my experience and hopefully avoid a 4 month (and counting) nightmare.
Get Confirmation That it’s Roof Rats
First of all, it’s important to know what you’re dealing with! I thought I had a raccoon and a couple of field mice skulking around after dark! Not a big deal! My grain is protected and my chicken coop is secure. When I started hearing nightly (and daily) wrestling matches (think WWF- critter edition) above my ceiling and saw mouse droppings along my top fence rail, that’s when I started paying attention. Rodent droppings aren’t hygienic and bio-security is important around here. I talked to my landlord and walked around for the next few days with “Little Bunny Foo-Foo” stuck in my head.
When the exterminator informed my landlord and I that we had rats, it was like when someone mentions the word ‘lice’. I got the strong desire to crawl out of my own skin and run away. RATS?!?! Like… bubonic plague carrying, baby biting, gross sewer-dwelling monsters of the night?!? Yep… those ones! Well… sorta. Roof rats aren’t sewer dwellers as a rule but still… gross!
Read about how to tell if you might have a roof-rat problem in my post: 4 Telltale Signs You’ve Got Roof Rats
So… I’ve Got Roof Rats. Now What?
Once we’d established that roof rats had taken up residence in the attic, the exterminator very patiently walked me through the options. Rat eradication breaks down to two categories: chemical and physical.
On the chemical side, there’s always poison. It’s quick, it’s toxic and it’s a non-starter for me. I’m not willing to have poisoned rat poop spread all around my yard for either my pets to find or my soil to absorb. The other popular chemical treatment is an anti-coagulant. It’s non-toxic but takes longer since the rat needs several doses of it and basically bleeds to death internally over several days (not a pretty picture, but that’s how it works). Both of these chemical methods are usually placed in a pet & child safe “bait box” that’s only accessible to the rat. In my later research, I found a company that has developed a liquid rat “sterilizer” that looks really promising for the future of rat control. They’re not yet approved in CA but are in many other states and got EPA approval last year.
On the physical side of rat removal are traps. Old fashioned snap-traps are the choice of the pros, because they’re effective (I found this out the hard way). They’re designed to kill the rat immediately and humanely… if they’re done right.
The exterminator set a couple of snap traps in the attic and bait-stations with anti-coagulant in the yard. He said we’d be rat free in 4-6 weeks.
How Did I Get Roof Rats?!?!?!?
At first, I took this rat infestation as a shameful personal slur. How had this happened!? I’m a reasonably clean, definitely sanitary person and pride myself on keeping a healthy homestead. To my credit (and yours if you’re dealing with them), roof rats are not attracted to filth (or chickens as some sites claim). They’re attracted to food and accessible places off the ground (like attics & palm trees) for a safe place to nest & multiply. Google “how did I get roof rats?” and what comes up is a list of sites talking about how to get rid of them, not how you got them. It’s not personal; it’s just food and shelter.
There are things you can do to help avoid them like keeping all outside grain and seeds in galvanized metal containers, don’t leave cat or dog food outside and keep hedges & trees at least 6 feet from your house. Oh yeah, and the two big ones I failed on… rodent-proof your compost bin & eliminate exterior entrances to your home and outbuildings. I’ve included a more detailed list at the end of this post.
Our rats happened to migrate from a neighbor’s house and found the perfect combination of delicious eats (abundant fruit, organic garden, open compost bin, etc…) and unscreened attic vents for a nice, cushy pad to escape the daylight… Oops!
Roof Rat Facts
Now that I had these unwelcome house-crashers, I decided to learn more about exactly what I was dealing with. Here are some things I’ve learned about the most common rat in California.
- Are known to carry 18 types of parasites, diseases such as the plague, Rat Bite Fever, Typhus, Salmonella and Leptospirosis. Yeah, not things you want around you.
- Spend 90% of their life at least 4 feet off the ground
- Have been known to crawl into car engines and gnaw the wires.
- Really don’t do well in cold climates; they’re more of a tropical/ subtropical rat.
- Prefer a diet of fruits, nuts & seeds but will eat just about anything to survive… including animal poop and even each other if necessary (yeah, they’re gross).
- Peanut butter or snickers bars usually work better than cat food or meat as bait.
- Don’t usually travel more than 150 feet for food unless they have to.
- Will chew through cement, stucco, hardened plastic (soft is no problem at all), drywall, solid wood, caulking and aluminum if the incentive is great enough. Their jaws can deliver up to 1lb of actual pressure, which is enough to bite an adult human’s finger to the bone.
- Speaking of their gnawing abilities… rat teeth were the most popular wood carving devices in the South Pacific islands before European metal tools were introduced. Yeah… who knew, right?
- Are nocturnal, usually emerging after sunset to eat (although I have seen them out before sunset).
- Sexually mature at 2-4 months, live for up to 18 months and have at least 3 litters per year of 6-12 babies. A single female has been recorded to produce 56 offspring in a year.
- Live in “packs” made up of several males and 2 or more dominant females.
- Are neophobic, but very adaptable. They’ll avoid new scents, sounds and objects for about a week. This is why traps should be left in place for at least a week and ultrasonic, scent and flashing light deterrents don’t work for long (if at all).
- Climb and balance extremely well! They can climb utility wires, straight up brick, cement and most wood structures.
- Have terrible eyesight. They see only in lightness and darkness of color but make up for it with extraordinary hearing and sense of smell.
Many counties of California offer free outdoor rat inspections. Check your county’s website to see if you’re in an eligible area. San Diego’s is here.
6 Weeks In and It’s Still a Rat Party!
Right away, I rat-proofed my compost bin and sprayed peppermint essential oil (I read it would confuse their scent paths) all around the perimeter of my yard. 6 weeks later, I was ready to pull my hair out- they were still plentiful! The roof eaves couldn’t be sealed until the population decreased or they’d die off in the ceiling crawl space (and noxious odors would follow).
The problem was our abundant food supply. Between my berry bushes, passion fruit vines & my landlord’s citrus trees, it was still an organic all-you-can-eat rat buffet. The little buggers don’t even care if the fruit is RIPE! Each rat needs about a tablespoon of liquid per day to survive, so any moisture-laden fruit or plant (they even gnawed through my borage plants) will sustain them.
I had really hoped the bait boxes and snap traps would be enough to end our rat troubles, but alas, stronger measures needed to be taken. I steeled myself and worked to pull up the red carpet and replace it with a big “UNWELCOME” sign. I tearfully (seriously… I cried) hacked my passion fruit vines to virtually nothing. My passion fruit vines are glorious and provide over 10lbs of fruit per season. To chop them down just after they’ve started to set fruit was downright painful. I turned their sacrificed foliage into bio-dynamic mulch though, so their glory lives on through the soil. Circle of life!
I removed all the boysenberries from my bushes, tore up my borage and generally made my homestead a barren, rat-unfriendly place to be. I delayed planting my garden and I decided to supplement the bait-stations with traps of my own.
The multiple-trap approach.
When I first added traps to the yard, I had this idealistic, sort of ‘spiritual’ notion to live-catch and relocate the rats to the nearest canyon. That way, they’d have a chance to live peaceably… or at least feed the local wild life. I felt sad for these loathed creatures. I mean, they don’t know they’re disgusting! They’re just going along, doing their little rat things and trying to survive. Many weeks later, I now relate to Bill Murray’s character in Caddyshack. If the rats burrowed, I’d probably consider blowing them out of there with dynamite. I know… not very spiritual of me, but it’s real.
What happened was that NOTHING worked well! I tried live traps, electric traps and “T-Rex” snap-traps, all with the intention of being humane. The live traps only caught a few babies. The two brands of electric traps I tried were both a huge disappointment. Not only did the rats avoid them completely, but I started seeing rats before dusk (not normal & can mean a population surge). Twice, I caught them in the chicken run helping themselves to food while the girls were out foraging! I chose to end them quickly with a shovel. I cried and apologized to the first departed rat for taking its life. The next time, I didn’t even flinch.
The “T-Rex” snap-traps worked the best out of the three, but still not great. I caught 3 rats total in 3 weeks but one of them was still alive when I found it the next day (definitely NOT an instant, humane kill). Mostly though, the bait was eaten out of the bait cups without the trap snapping.
13 weeks in and finally, a trap that works!
By this time, my landlord and I were both running out of patience with the process and wanted to cut off their nest access. The exterminator finally sealed the roof eaves and put extra snap traps in the attic twelve weeks from the initial consultation. Hopefully, with all the remaining rats that would be dispatched quickly with the attic traps.
We were well into May by then and I was chomping at the bit to FINALLY plant my garden! I put the T-Rex traps all around my garden beds and just went for it. What a mistake! My seedlings were either trampled or chomped on. My corn, zucchini and cucumber seeds were dug up and eaten repeatedly.The trap bait cups were still emptied without snapping.
Honestly, at this point I considered poison. I didn’t linger there for too long, but it happened.
In desperation, I decided to give the exterminator’s wooden snap traps a try. Halle-freakin-luiah, they worked like a charm! Seriously, I should have started with these! It took three NIGHTS (not weeks) and I had the main garden culprits in the traps! As advertised, they were both instantly, humanely dispatched.
The wrap up
So here we are in June, about fifteen weeks into this ordeal and at long last, getting some traction. At this point the exterior is completely sealed and it seems as though they’re all gone from the ceiling crawl space. The yard is baited with extra bait-boxes and fortified with the wooden snap traps (out of reach for the fur & feather kids of course). It’s been several days now with ZERO rat activity. Once we’re sure they’re gone, the next (and final) step is the clean-up. Gratefully, that’s also being handled by the exterminator. It’s important that rat droppings are handled properly and not allowed to go airborne!
If you are starting a garden, getting chickens, have citrus, nut, or palm trees and/or are dealing with roof/citrus rats, here are my recommendations from personal experience:
To avoid rolling out the red carpet for roof rats:
- Secure your house! Make sure there are no holes bigger than ½” in size on the exterior. Any absent vent or eaves screening needs to be fixed with galvanized metal mesh (1/4″ mesh will protect against both rats and mice) and holes need to be plugged with steel wool before patching with plaster, stucco or putty.
- Keep foliage off the ground by at least a foot, and avoid foliage up your walls (like ivy).
- Cut tree limbs so that there are at least 6ft between where the tree ends and your roof begins.
- If you have overhead utility lines and you know roof rats are prevalent in your area, consider getting rat guards (but be aware there are potential risks to your wiring with this measure)
- Avoid feeding your chickens on the grass or ground, use dishes and remove all spillage in the yard
- Keep all outside pet food & water sources absent overnight.
- Make sure your compost bin is rat-proof (here’s how)
- Keep all stored grain, nuts and seeds in galvanized metal containers.
If you have roof rats here are some steps to resolve them:
- Skip the marketing ploys and get the old-fashioned wooden snap traps by Victor. They are MUCH more effective than the plastic T-Rex Jaw or electric traps! In my experience, they are also the most humane. Try sliding a flat seed like pumpkin or other squash in the bait tab and then slathering it in peanut butter. That’s worked the best for me.
*** Make sure to use disposable nitrile gloves WHENEVER handling the traps so that your scent does not transfer to the trap and scare the rat away!****
- Anti-coagulant bait boxes may work but I haven’t seen any dead rats around except for the ones in the snap traps
- Check your house, outbuildings & chicken coop regularly for new holes or chew marks and make sure they’re sealed properly.
- Clean up all pet waste right away.
- Remove ALL of your moisture-laden plants, fruits & vegetables (ripe and unripe).
- Cut back vines and large hedges (like bougainvillea) to just a few sections and leaves. Rats won’t nest where there’s daytime light. Your perennials will bounce back. Remember to save all that plant material! It makes MUCH better mulch than straw or leaves alone! You can read about making bio-dynamic mulch here.
- Clean up rat droppings by wearing gloves, a respirator and spraying them first with a disinfectant. DO NOT SWEEP OR VACUUM THEM! Read the CDC instructions here
This rat drama has really been a frustrating and lengthy process. I’m hoping that it is now drawing to a close. Looking back on it, having the vents completely screened in and the compost bin rat-proofed from the get-go probably would have prevented the infestation.
I hope you can gain something from my experience… even if it’s what not to do!
I’m happy to answer any questions and offer assistance where I can! I’d also love to hear about your experiences in dealing with these persistent pests! Please share in the comment section below!