The following article was originally
printed in Shared Space, the PAWS
Habitat Conservation Program newsletter.
by Kevin Mack, PAWS Wildlife Naturalist
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.
improvements such as brush piles will help attract wildlife to your
property, however, you should be prepared in case conflicts arise.
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
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
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.
Expanding foam insulation and steel wool combine to make an effective barrier to rodents.
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.
animals were released between November 30th
and December 2nd, 2005. Thanks to all of
you for helping to make these releases possible!
- 1 Glacous-winged Gull
- 1 American Robin
- 1 Black-capped Chickadee
- 1 Herring Gull
557 wild animals have been released since the beginning of 2005.
Thanks to all of you for helping to make these releases possible!
All rights reserved.
©2005 Progressive Animal Welfare Society
A Northwest leader in protecting animals since 1967, the Progressive Animal Welfare Society (PAWS)
shelters homeless animals, rehabilitates injured and orphaned wildlife, and empowers people to
demonstrate compassion and respect for animals in their daily lives.