The rats in the walls
Jan. 25th, 2024 07:18 pmWhen a massive avocado tree grows over your house, you are prime territory for a rat invasion.
What's amazing, really, is that it took eight years for them to invade. It was the pandemic that did it. People weren't out dropping food or stuffing the garbage cans around the lake, so there was a mass-migration of hungry rats out of public spaces and in towards housing.
Every avocado that fell in my back yard was a delicious rat lure. The tree itself was too vertical for them to climb, and a hostile terrain because squirrels lived up there, but eventually some of them learned they could climb the bay tree in my front yard, leap from there to an electrical wire, and walk along that to the corner of the house. From there they chewed an access hole and colonized my attic, where they could make nests away from the squirrels, who have been known to devour rat babies whenever they find them.
You may recall, I used to have a problem with squirrels in the attic space, but after a while of excluding them and trimming back the trees it became an inconvenient place for them to nest, and they stopped bothering me. But the rats couldn't use the tree, and they didn't mind the commute to the roof.
I was relatively fortunate: They never chewed their way down into the cabinets and pantry of the upstairs unit. They preferred to go running back out along the wire and feast on the avocados littering the yard.
The first thing I did was consult experts and call around. Out of eight different pest control companies I called, two got back to me.
The first inspector stood in the driveway and looked up at the hole, then shook his head.
He said, "If that hole is fresh, it could be just one rat trying to set up a good nesting area. But that only takes about 3 weeks. So if it's been longer you might have offspring in there already. Rats need to go outside and find water every night, so you're going to get a lot of traffic through there until the babies are grown up. And then, they won't leave... They'll just make more nests."
After this grim prognosis, the inspector told me he preferred to work with access holes near the ground, where he could crawl inside, or reach inside and place traps that could be anchored in place. So if a rat got caught, it couldn't drag itself away and die somewhere inaccessible. The stink of a decaying rat is atrocious and lasts for months. Since I was dealing with a hole way up on the side of a tall house, he said the most he would do is climb up there and shove poison inside. The poison makes rats very thirsty, sending them in search of water, so they're less likely to die in the walls.
The company typically offered a two-year guarantee against re-infestation, but he wouldn't for me, since he didn't like the idea of putting a ladder up against the house every time he had to come out and deal with another rat.
He apologized, and took off in his truck. No help there.
The second company was better. The inspector went to the top floor of the house and leaned out the window, getting a close look at the hole. There were no droppings along the tin-coated ledge, which was a good sign. He said the whole setup was too precarious for him to take on, but he did have some advice, in the form of a story.
"Back when I was just starting out in the pest control business, I got called out to a vineyard. They had a big problem with rats nesting in the top floor of the barn. The problem was, nobody could figure out how the rats got up there. It was a storage loft with no stairs, just this open space, and there was all this equipment below so you couldn't get a ladder there."
"I looked around and figured the only way they could make it was by going up along a beam, maybe eight feet away, and then jumping off the wall, doing this parkour move to bounce over to the ledge. So I climbed up there with a hammer and nailed a bunch of old-fashined rat traps along the wall. The owner was looking at me like I was an idiot. I could tell he wanted to ask me, 'you think rats can fly?' Well, no, but rats can jump. They can jump really far."
"So I nailed up four traps that way, and we came back in a couple days. All the traps were sprung. Two had dead rats hanging in 'em. I reset the traps and we kept coming back, and so did the rats. I caught at least a dozen more like that. It's not how I usually do it, and I'm too old to be climbing around on tall ladders now, but maybe you can try something similar."
I thanked him and we shook hands. Then I went out and bought some supplies.
A big box of ten old-fashioned heavy duty wooden rat traps. Touchy and dangerous to work with, but adaptable. Plus some stinky cheese and some peanut butter.
I drilled two pilot holes through each trap, then put deck screws partway in the holes. The traps went into a sack, along with the screwdriver and the bait, and then it was time to climb up there and attach them...
Some hard-won advice: Put on some disposable rubber gloves, and use them the entire time you handle the traps and apply the bait. Rats can smell even the smallest whiff of human contact, and will steer away from the source.
It was really not fun climbing up that ladder, and using both hands to screw traps onto a wall. I had to try a couple different arrangements, too.
I was really worried the squirrels would get fouled up in them, and then I'd have injured squirrels thrashing around and dying on the side of the house. The squirrels have been a consistent nuisance, but they have so much personality. I'd feel bad injuring them. I felt bad about killing rats too, honestly, but I couldn't let them keep tunneling into the roof and crapping in the ceiling over the tenants. They could also start chewing on the wiring and start a fire.
To my relief, the squirrels jumped well clear of the traps. They had zero interest in them.
It wasn't long before I started catching rats.
Some days I'd come out and both traps would be sprung with all the bait gone, and I'd have to climb up there to do a reset. Other days I would see no activity at all. For a while, birds would fly over and spring the traps, then eat the bait while perched nearby. I got worried I would kill birds instead of rats. Sadly, I did catch one, but the rest were fast enough.
I kept traps up there, rain or shine, for about a month. The tally was six dead rats, all adults.
It was very hard to know if I'd caught them all. I left the traps up there for another week and got nothing. I used my tree trimming stick to cut all the foliage off the top of the bay tree, and pulled down a bunch of vines. That seemed like enough, but then during the late winter rains, the tenants reported hearing the sound of rats chewing on wood inside the house again. So up the ladder I went, and caught four more rats.
Then, at long last, it was time for the painters to start. They had a carpenter on staff who repaired the hole in the roof and then hammered an aluminum plate over the area, which would discourage rat teeth the same way it discouraged squirrels. Things went quiet for a while, then the tenants reported hearing more rat teeth, on the far corner of the house. I climbed up there and looked inside the gutters, and saw another hole.
The painters had come and gone. This repair would have to wait for a roofer. In the meantime, I could at least discourage further colonization by making the commute longer. I cut more material off the top of the bay tree, and set some modern "enclosed" traps in the back yard at ground level. One more dead rat in those. Later on, the tenants reported seeing a rat in the driveway. They suspected it was hanging out in the storage nook under the stairs, so we cleaned up the foliage around that, and redistributed the enclosed traps.
Then one morning I came outside and found a single dazed rat wandering around in the bottom of the cement landing by my front door, apparently too weak or sick to escape. Mira was perched nearby, gazing at it warily.
I'd done enough death-dealing. I coaxed it into a bag and took it a few blocks over to a park and let it go.
Then the noise and activity stopped.
In summary, it took two entire years to get the rats out of the house, and there is still one entry point that needs fixing. But I count myself lucky. The damage could have been a lot worse, and the tenants were very tolerant and helpful through the entire ordeal.
What's amazing, really, is that it took eight years for them to invade. It was the pandemic that did it. People weren't out dropping food or stuffing the garbage cans around the lake, so there was a mass-migration of hungry rats out of public spaces and in towards housing.
Every avocado that fell in my back yard was a delicious rat lure. The tree itself was too vertical for them to climb, and a hostile terrain because squirrels lived up there, but eventually some of them learned they could climb the bay tree in my front yard, leap from there to an electrical wire, and walk along that to the corner of the house. From there they chewed an access hole and colonized my attic, where they could make nests away from the squirrels, who have been known to devour rat babies whenever they find them.
You may recall, I used to have a problem with squirrels in the attic space, but after a while of excluding them and trimming back the trees it became an inconvenient place for them to nest, and they stopped bothering me. But the rats couldn't use the tree, and they didn't mind the commute to the roof.
I was relatively fortunate: They never chewed their way down into the cabinets and pantry of the upstairs unit. They preferred to go running back out along the wire and feast on the avocados littering the yard.
The first thing I did was consult experts and call around. Out of eight different pest control companies I called, two got back to me.
The first inspector stood in the driveway and looked up at the hole, then shook his head.
He said, "If that hole is fresh, it could be just one rat trying to set up a good nesting area. But that only takes about 3 weeks. So if it's been longer you might have offspring in there already. Rats need to go outside and find water every night, so you're going to get a lot of traffic through there until the babies are grown up. And then, they won't leave... They'll just make more nests."
After this grim prognosis, the inspector told me he preferred to work with access holes near the ground, where he could crawl inside, or reach inside and place traps that could be anchored in place. So if a rat got caught, it couldn't drag itself away and die somewhere inaccessible. The stink of a decaying rat is atrocious and lasts for months. Since I was dealing with a hole way up on the side of a tall house, he said the most he would do is climb up there and shove poison inside. The poison makes rats very thirsty, sending them in search of water, so they're less likely to die in the walls.
The company typically offered a two-year guarantee against re-infestation, but he wouldn't for me, since he didn't like the idea of putting a ladder up against the house every time he had to come out and deal with another rat.
He apologized, and took off in his truck. No help there.
The second company was better. The inspector went to the top floor of the house and leaned out the window, getting a close look at the hole. There were no droppings along the tin-coated ledge, which was a good sign. He said the whole setup was too precarious for him to take on, but he did have some advice, in the form of a story.
"Back when I was just starting out in the pest control business, I got called out to a vineyard. They had a big problem with rats nesting in the top floor of the barn. The problem was, nobody could figure out how the rats got up there. It was a storage loft with no stairs, just this open space, and there was all this equipment below so you couldn't get a ladder there."
"I looked around and figured the only way they could make it was by going up along a beam, maybe eight feet away, and then jumping off the wall, doing this parkour move to bounce over to the ledge. So I climbed up there with a hammer and nailed a bunch of old-fashined rat traps along the wall. The owner was looking at me like I was an idiot. I could tell he wanted to ask me, 'you think rats can fly?' Well, no, but rats can jump. They can jump really far."
"So I nailed up four traps that way, and we came back in a couple days. All the traps were sprung. Two had dead rats hanging in 'em. I reset the traps and we kept coming back, and so did the rats. I caught at least a dozen more like that. It's not how I usually do it, and I'm too old to be climbing around on tall ladders now, but maybe you can try something similar."
I thanked him and we shook hands. Then I went out and bought some supplies.
A big box of ten old-fashioned heavy duty wooden rat traps. Touchy and dangerous to work with, but adaptable. Plus some stinky cheese and some peanut butter.
I drilled two pilot holes through each trap, then put deck screws partway in the holes. The traps went into a sack, along with the screwdriver and the bait, and then it was time to climb up there and attach them...
Some hard-won advice: Put on some disposable rubber gloves, and use them the entire time you handle the traps and apply the bait. Rats can smell even the smallest whiff of human contact, and will steer away from the source.
It was really not fun climbing up that ladder, and using both hands to screw traps onto a wall. I had to try a couple different arrangements, too.
I was really worried the squirrels would get fouled up in them, and then I'd have injured squirrels thrashing around and dying on the side of the house. The squirrels have been a consistent nuisance, but they have so much personality. I'd feel bad injuring them. I felt bad about killing rats too, honestly, but I couldn't let them keep tunneling into the roof and crapping in the ceiling over the tenants. They could also start chewing on the wiring and start a fire.
To my relief, the squirrels jumped well clear of the traps. They had zero interest in them.
It wasn't long before I started catching rats.
Some days I'd come out and both traps would be sprung with all the bait gone, and I'd have to climb up there to do a reset. Other days I would see no activity at all. For a while, birds would fly over and spring the traps, then eat the bait while perched nearby. I got worried I would kill birds instead of rats. Sadly, I did catch one, but the rest were fast enough.
I kept traps up there, rain or shine, for about a month. The tally was six dead rats, all adults.
It was very hard to know if I'd caught them all. I left the traps up there for another week and got nothing. I used my tree trimming stick to cut all the foliage off the top of the bay tree, and pulled down a bunch of vines. That seemed like enough, but then during the late winter rains, the tenants reported hearing the sound of rats chewing on wood inside the house again. So up the ladder I went, and caught four more rats.
Then, at long last, it was time for the painters to start. They had a carpenter on staff who repaired the hole in the roof and then hammered an aluminum plate over the area, which would discourage rat teeth the same way it discouraged squirrels. Things went quiet for a while, then the tenants reported hearing more rat teeth, on the far corner of the house. I climbed up there and looked inside the gutters, and saw another hole.
The painters had come and gone. This repair would have to wait for a roofer. In the meantime, I could at least discourage further colonization by making the commute longer. I cut more material off the top of the bay tree, and set some modern "enclosed" traps in the back yard at ground level. One more dead rat in those. Later on, the tenants reported seeing a rat in the driveway. They suspected it was hanging out in the storage nook under the stairs, so we cleaned up the foliage around that, and redistributed the enclosed traps.
Then one morning I came outside and found a single dazed rat wandering around in the bottom of the cement landing by my front door, apparently too weak or sick to escape. Mira was perched nearby, gazing at it warily.
I'd done enough death-dealing. I coaxed it into a bag and took it a few blocks over to a park and let it go.
Then the noise and activity stopped.
In summary, it took two entire years to get the rats out of the house, and there is still one entry point that needs fixing. But I count myself lucky. The damage could have been a lot worse, and the tenants were very tolerant and helpful through the entire ordeal.