Stories of a Wildlife Encounter - "Excluding Conflicts"
By Naturalist Kevin Mack from Earth Share organization PAWS Wildlife Rehabilitation Center, published in the December14, 2005 edition of Wild Again
About three months ago, I moved into a rental house in Edmonds that has a very wildlife friendly yard. The property contains several large fir and cedar trees, many rhododendron bushes, an apple tree, ferns, and other native vegetation. The “lawn� on this property consists mainly of mosses, and no chemicals are ever used on it. Bird baths in the front and backyard provide a year-round water source for wildlife, and a ladder built up and over the fence provides easy passage for raccoons, squirrels, opossums and other mammals as they move through the area. The fact that this relatively urban piece of property plays host to an abundance of wildlife was one of the main things that made it appeal to me. But when wildlife and humans share space, there is always the possibility that a conflict will arise. I began to experience one such conflict shortly after I moved in.
Before the previous renter moved out, he had pruned a number of the trees on the property and created two large brush piles. I was excited about these as they added even more valuable habitat for snakes, salamanders, small birds, and small mammals to the property. And the piles were definitely being used. Winter wrens, and other small birds were frequently seen in and around them, and the outer branches of the brush piles were used by many species of spiders. The brush piles also attracted small mammals, and although many people might have found the Norway Rats and House Mice undesirable, I knew they would provide a valuable food resource for the owls, raccoons and occasional coyotes that visited my neighborhood. But rats being rats, and mice being mice, it wasn’t long before they took advantage of the warmer, more inviting quarters that they found nearby.
About a month after I moved in, I began finding signs that I had uninvited houseguests. I first noticed that my cats were paying a lot of attention to the area around the kitchen sink. I then began to find mouse and rat droppings around the garbage underneath the sink. A hole in the wall from recent plumbing work was providing the small mammals with easy access, and the garbage can was providing them with a steady food source. I removed the garbage from underneath the sink, and sealed off the hole from which the mice and rats were gaining access. I quickly realized that this was not the only access they had when I began to find droppings along a straight line from my cats’ food bowl to the area beneath the dishwasher. A quick inspection with a flashlight revealed that there was another hole in the wall behind the dishwasher.
The mice became more and more bold, coming out while I was in the room and even leaving little watercolor paint mouse tracks on the white table in the studio. Eventually I could smell the mice even when I couldn’t see them. It was definitely time to do something about the situation.
I contacted my landlord whose first suggestion was to trap the mice. I explained to him that trapping would only be a temporary solution, and that mice and rats are so abundant they would quickly repopulate the house. I convinced him that the problem was that the mice and rats had access to the house, not the mice and rats themselves. After having him over to the house, pulling out the dishwasher and showing him the buildup of urine and droppings behind it, it was clear to him that a permanent solution needed to be found
The first thing that had to be done was to seal up all holes that led from the crawlspaces in the walls to the inside of the house. The area behind the dishwasher was sealed, as was an area around a pipe that came up from below the house. This did not stop the mice and rats from having access to spaces in the walls, but it did cut off access to the main thing that was attracting them– food. Once they were no longer able to reach the indoor garbage can or the cats’ food, they were forced to forage outside the house.
The next goal of “operation mouse and rat eviction� was to identify and repair any external flaws on the house that would allow the small mammals to enter the walls or attic. Two damaged vents in the foundation were identified and sealed with 1/4 -inch vinyl-coated hardware cloth. The landlord and I found multiple holes in the wood siding that had once contained wires, or other pieces of hardware, but that now were wide open. One of them had visible chew marks around its perimeter, and appeared wide enough to allow access to animals as large as squirrels. We secured all of the holes by stuffing them with coarse steel wool and then filling them with expanding, hardening spray foam. The spray foam itself would be easily chewed by a persistent rodent, but the steel wool would present a much less desirable chewing surface. Also, the spray foam could be sanded down so it was flush with the wood siding and then painted over.
While we were sealing up the house, my neighbor who lives in small apartment attached to the house came out to ask what we were doing. When I told him, he said that he occasionally gets rats in his attic, but he just traps them. When I asked how long he has been trapping them, he replied, “About 18 years.� We proceeded to seal up all potential entry points around his place as well.
It has now been two months since we repaired all suspected entry points to the house, and there have been no further incidents with mice or rats. I periodically check the repairs to ensure that none have been breached, and so far they have not. By identifying and addressing the true cause of the conflict (the easy access to the house) it was possible to solve the problem without the use of traps, poisons, or other dangerous and undesirable methods.
In this example, the animals that we were dealing with were mice and rats, but it could have been any number of species. When you create good wildlife habitat on your property, you can never be sure which animals will show up to take advantage of it. When making plans for your yard, I encourage you to keep this in mind. Take a look at your house, garage and other structures and try to identify areas in which potential conflicts may arise. By proactively sealing up potential entryways, and removing attractants from areas that you would prefer wild animals not use, you will be ahead of the game when it comes to avoiding a negative experience with wildlife. If you provide good habitat, while minimizing the chances of conflict, your property will truly become a sanctuary.
For more information on how to address specific wildlife conflicts you may be experiencing, contact PAWS at 425-787-2500, ext. 817.
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#276 - Melanie Skeet
Kevin,
How could you be sure that at the time you did the work to your house, you weren't sealing any rats inside the house?
Melanie
#278 - Kevin Mack
Melanie,
In order to reduce the possibility that any rats or mice would be trapped in my walls, we performed the work on the house in two stages. During the first stage, we cut off all access between the crawlspaces and the living space of the house. This meant that rats/mice that were in the walls could no longer get to our indoor garbage can, cat food, or human food, but they could still leave the walls and get outside. The assumption was that they would have to leave to find a new food source once they lost access to their current supply.
I didn't work simply on assumption though. I had two highly sensitive mouse detectors working for me...namely my cats, Henry and Oliver. Their behavior had been the first indication that mice and rats were living in the walls, and I watched them closely to try to get a clue as to when the mice and rats were gone. For a few days after the interior of the house was sealed off, Henry and Oliver occasionally reacted as if they were hearing mice in the walls, but eventually they showed no further indication that they heard anything out of the ordinary. After more than a week with no noticeable mouse detection from the cats, the landlord sealed up the holes on the outside of the house.
After the outer holes were sealed, I never heard any scratching or chewing in the walls, and the cats did not indicate that they detected anything either. This gave me a fairly high degree of confidence that I had not inadvertently trapped any animals in the walls.
If I didn't have cats, I would have sealed up all outside holes except for one, and then I would have placed a one-way door device over the single remaining hole. This would have allowed mice and rats to leave but not return.
Kevin
#318 - Melanie Skeet
Kevin, thanks for that reply. I never would have thought of a one-way mouse door!
I'm just about to embark on rodent -proofing works. Two years ago we had someone come and put poison down in our cellar as we had found rat carcasses (long dead) under some floorboards. This was a big mistake as we had three rats die under the floor, which were unbearably smelly and very costly and difficult to locate. We repaired some broken air bricks and thought the place was safe, but recently I recognised the familiar cabbagey smell again. It has only lasted a couple of days so my guess is that it was a dead mouse this time. There's no evidence of anything getting into the kitchen food cupboards, just the cellar, which only has wine bottles in it. I can't even find any signs of shredded cardboard down there, so I guess they are sheltering from the cold outside. (I live in England) Unfortunately we don't have a cat. That would be useful right now. I'm going to try fixing some fine wire mesh across the spaces at the top of the cellar walls first of all, then I'll search for holes outside.
I 've been told that rats and mice never live in the same house together as rats will eat the mice. Do you know if this is true?
Melanie
#322 - Kevin Mack
Speaking from my recent experience, rats and mice can apparently coexist in the same house. While rodent proofing my house, I found both fresh rat droppings and fresh mouse droppings. Perhaps if the two species had been allowed to live in my walls longer, the rats would have eventually won out, but at the time I took action both were calling my house home.
Kevin