There is an invasion of mice. What can we do?

March 2014


Recently I’ve had an invasion of mice to my town house. Any small holes where pipes etc came into the house were filled in and a selection of traps and baits were put in strategic places (always using gloves in case the scent of my hands might deter the mice from using the traps). I’ve used a range of pre- baited, humane and conventional traps.

To the delight of children, who came to observe them at play, the micenever came close enough to the traps to get caught. They circled the traps. I don’t want to use poison for fear of a corpse causing a bad odour as was the first evidence of these creatures coming indoors .A corpse was eventually found in the wall cavity by removing skirtings and plaster.

These mice do not have any interest in pre-baited traps or chocolate, peanut butter or cheese. Now I’ve plugged in an electronic device into a socket and maybe the mice are gone or are they just waiting for another opportunity. There are plenty of cats about but they seem to sit in wait for the birds.


An invasion of mice can be difficult to overcome, as you seem to be experiencing. As mice can multiply quite quickly and are unsanitary, it is essential to ensure you get rid of mice in your home as quickly as possible.

Mice look for food and shelter most frequently in colder months and many people are faced with this problem in winter and early spring.

You mention you have filled any small holes where pipes enter your house, however you don’t mention what materials you have used.

If your mice reappear, it is worth knowing that a mouse can enter a premises where there is a hole merely large enough to fit a Biro.

Expanding foam is ideal for filling any cavities as it can be sprayed into any holes or gaps and will expand and harden upon coming in contact with the air. Mice are very good at finding small gaps (air vents are a common entry point).

As you are aware, eradicating mice can be a process of trial and error. It may well be the case that the electronic device you have plugged in has solved your issue. It is worthwhile laying some talcum powder along the floor beside the walls; you will notice track marks within a few days if your mice are still present.

Your mice appear to be quite smart so if your problem resurfaces, you may need to trick them into trusting you. Pre-baiting your traps with peanut butter (as before) and not setting them for a few nights may make your mice believe this is a safe food source.

Once the traps are set you may th en be successful in catching them. A piece of bacon can work well as bait. Lay the traps close to the wall.

Sometimes, people think that they have mice but actually have pygmy shrews which are a protected species. If your “mice” have no interest in peanut butter, it is possible that they are shrews.

If all else fails and your problem persists, I would recommend contacting your local pest control company. They are well experienced in this area and are well-equipped in dealing with invasions of this kind.

Simon Stokes is a chartered surveyor and estate agent and chair of the residential property professional group of the Society of Chartered Surveyors Ireland .