The Field Mouse and Poison
As a pest control technician, I get called to all manner of rodent related issues, rats and mice being the primary issue effecting the average homeowner. However, proper identification of the rodent species is crucial in more ways than one. Rats and mice may look similar to the uninitiated (not withstanding size differences) but have very different behaviours and priorities, rats being concerned with finding a free water source for example, whereas mice take most of the moisture they need from their food sources.
But there is another problem, if the infestation is found to be mice……then what species of mouse are we dealing with? This may sound like it doesn’t matter but it matters a lot. The house mouse (Mus domestica) has been with humans, side by side for thousands of years. Taking the scraps that we leave behind and taking shelter in our homes, outhouses and spoiling raw food sources. This is by no means a choice on our part, and they are still with us after all of this time despite the measures we’ve taken to stop them including poisoning.
But there has been an increase in my area of Kent (Maidstone) of a different
kind of mouse which has so far not been considered a pest species, as it has historically been considered a rural animal and thought to be confined to hedgerows and bushes. The Field Mouse, sometimes known as the Wood Mouse has been increasingly entering
into peoples houses via broken air bricks, gaps and other small holes. This issue in my experience is on the increase, especially in houses in more rural areas.
Why is this an issue?
Well, the Wood Mouse is far more inclined to enter your home via these channels, but unlike the House Mouse they will leave the house for long periods to forage for food which means they are more than likely to die of the poisoning whilst not in your home or be predated on whilst having poison in their system. Therefore, when they are eaten by a predator i.e., an owl or a bird of prey they can then pass the poison on to them causing them harm which can be fatal in some cases, this is known as secondary poisoning. This means, and quite rightly, that the use of toxic bait has been legally banned for use against the Field mouse. Indeed, any species of rodent other that the Norway Rat and the House Mouse cannot be controlled by any poison. Only physical control such as mouse traps are permitted.
In my experience over the last eight years of pest control, and as more land is being used to build houses, the call outs for field mice have increased due to displacement and scarcity of food sources.
So, what is the best course of action?
In my opinion the best way to prevent Field mouse issues in your home, indeed any rat or mouse species is always proofing of entry holes whether that be missing bricks, damaged air bricks or gaps around pipes. This will stop any rodent in their tracks and make your house less accessible to them. So, take the time this winter as the weather changes to look around your house for any holes bigger than 5mm approximately and fill them in, protecting you from rodents this winter.