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5 Signs of a mouse infestation

Top tell-tale signs that you have mice

1. Mouse poop, also known as faeces, droppings – often around the base of kitchen units, near boilers and in lofts.

2. Noticing nests or shredded/chewed materials or damaged food packets.

3. Seeing a live mouse in the daytime, often indicates a large population is present.

4. Gnawing marks commonly on wood, paper, furniture, pipes and electrical cables.

5. Hearing scratching, or scuttling noises, usually when things are nice and quiet. Mice are most active at night when humans are generally not around.

PestWise offer a short course on Pest Awareness which covers what to look for and where.

Mice UK: Signs

Mouse Behaviour & Biology

What is the lifecycle of a mouse?

Mice typically have 5-7 pups and they can have 5-10 litters per year; add to that the fact that they can start re-producing at  8-9 weeks old and you can see how quickly a couple of mice can turn into a serious mouse infestation.

What does the term commensal rodents mean?

House mice are often referred to as commensal which means they live in close proximity to humans.

Do mice hibernate?

Mice are an issue throughout the year as they do not hibernate. Our buildings are nice and warm with central heating and very often have all the factors mice need to survive throughout the year.

Can mice swim?

Mice are good swimmers, but generally avoid water unless they need to.

Can mice climb?

All mice are good climbers, however, house mice are particularly agile climbers due to their longer tails and very often will seek higher / out of the way areas to hide and make their nests.

Can mice jump?

Mice are able to jump up to 24cm high, like other animals they can also fall from great heights without injury.

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What is the difference between a house mouse and a field mouse?

Apart from the obvious names they have been given, house mice will also live in offices, factories and domestic properties; Field mice can live indoors, but generally they prefer outdoor environments. 

The house mouse has smaller ears and eyes than a field  mouse. A field mouse has chestnut brown fur and a house mouse has light brown fur.

Where do mice nest?

House mice will utilise almost any internal areas that provide the basics for their survival – food, somewhere to build a nest and favourable temperatures (however mice have also been known to nest within freezers). 

Generally within an office or factory, mice will make a nest in voids created during construction, be that within raised floors where cables pass below, suspended ceilings or even wall cavities. Data cable runs in offices are generally tucked out of the way, provide a harder surface to gnaw and also a network to migrate around a building.  These are very often over looked by pest control companies as they are harder to access.

Within factories mice can live within food production machines, especially where there is less requirement for inspections / maintenance; exiting their safe domain when all things are quiet and they search for food scraps.

Farms are equally at risk from house mice, often once they have been accidentally transported to site – nesting in storage boxes, equipment such as combines which are stationary for much of the year, even rugs for animals or within feeding stations themselves.

What do Mice eat?

Mice will eat pretty much anything depending on the environment they are living in, however cereal and grains are a favourite.  They are very adaptable to their environment and will learn how to survive quickly. Within offices, mice will often move in random pathways searching for any food scraps and then quickly bolt back to a quiet location to eat their prize.

Do mice need access to water?

Normally mice obtain sufficient hydration from their food sources so don’t need a dedicated water supply.

Do mice spread diseases?

Mice scatter their droppings (i.e. don’t have a fixed location) as well as mark their territory by urinating as they travel along their runs and scent mark in places where they feel secure such as somewhere to frequently eat or nest. Every time they do this they are potentially spreading harmful diseases such as Salmonella and Listeria via their urine, droppings or bedding.

Food poisoning is a particular high concern where mice are present as they spread dirt and bacteria on worktops, cupboards, food stores and on anything else they scurry over.

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Why do mice need to be controlled?

Mice are a serious threat to public health as they carry many unpleasant diseases some of which can be fatal, a few of the risks are: - Leptospirosis (Weil’s disease), Hantavirus, toxoplasmosis,  and Salmonella.

Mice also pose a serious threat to damage of property as they gnaw to keep their teeth in perfect condition. Mice can be a fire hazard if they gnaw electrical cables, there is also a risk of flooding from them chewing on water pipes. The annual cost of damage and lost information from data cables within offices and factories is impossible to calculate, but it will run into many hundreds of thousands of pounds and is often not associated to mice damage, but wear and tear.

Mice are potentially a huge problem to businesses posing a risk not only to their reputation, but in food environments mice infestations can be forced to close by Environmental Health Officers (EHOs) from the Local Authority.

Properties also face financial implications from not following their legal obligations under the Prevention of Damage by Pests Act 1949, fines for non-compliance can be hefty.

Anyone operating a food business also has to ensure they follow the Food Safety Act 1990 which requires the premises to be kept free from pests in accordance with their statutory due diligence duty of care.

PestWise can review your pest management procedures and work with you to ensure best practice and check you are complying with pest control legal requirements.

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How to get rid of mice

Do it yourself products such as Mouse poison (generally referred to as Mouse bait or rodenticide) for getting rid of Mice are available; however due to the adaptive nature of Mice, they are not always easy to control with a simple feed bait and often the restrictions placed on the use of bait do not match the behavioural conditions of mice

Amateur use rodenticides can be purchased over the counter, but will generally be more expensive and often in smaller quantities.  Professional quantity baits now require a Campaign for Responsible Rodenticide Use (CRRU) certificate. PestWise can provide all the necessary training and advice required to purchase Mouse bait and help with a strategy within a building to eliminate and prevent mice activity.

Additionally many Mice have developed resistance to Mouse poison meaning that most bait is ineffective.  PestWise works with Reading University into the geographical development of rodenticide resistance, mainly resistance of mice in London and other cities.

When trying to control mice some of the common methods and products used are:-

  • Mechanical Mouse Traps

  • Electronic Traps

  • Mouse Cages (Live Catch) used for humane Mouse control

  • Mouse Glue Trap

  • Mouse Poison (also known as Mouse Bait or Rodenticide) and

  • Mouse Sonic Repeller units

For more information on how to control rats complete one of our pest awareness courses

Other key things to be considered other than extermination of mice are some more pro-active methods:-

How to prevent mice:-

  1. Prevent mice in your house by filling gaps around pipes and buildings, ideally with a material such as wire wool or concrete. Use expanding foam with caution – often in combination with other filler materials such as wire wool.

  2. Keep basements, storage cupboards voids and lofts tidy and clear of clutter and debris and especially food related rubbish or items that can be used as nesting materials.

  3. Keep refuse areas clean and tidy and ensure that bins have tight fitting lids and are emptied frequently.  Make sure internal bins are not left with food overnight and clean up any spillages.

  4. Avoid leaving food in accessible areas, make sure food is stored in airtight containers.

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Mice Common Questions

Is it a mouse or baby rat?

A young rat can easily be mistaken for a large adult mouse, they can also be mixed up with shrews and voles. It’s important to correctly identify the species you are dealing with to ensure correct & proper treatment, especially as water voles and shrews are protected species and along with field mice are beneficial for the local environment.

Mouse vs rat Droppings, what is the difference?

Mouse droppings have blunt ends and will be around 2cm long whereas mice droppings have a more pointed end and are less than 1cm long. INSERT IMAGE

What size gap can Mice fit through?

Mice only need a small hole of around 5mm to squeeze through.

There are mice within the raised floor, what can I do?

Dealing with mice under floors and in cavities in  offices is one of the most difficult areas to deal, access points need to be established and paths of migration need to be identified.  PestWise are specialists in tracking and identifying how mice are taking advantage of underfloor gaps and voids.

How do I know if I have a field mouse or a house mouse in the house?

It is more likely to be a field mouse in the colder weather as outdoor food sources decline and they look for a warmer place to nest. Unless you see the mice  it will be difficult to make a positive identification either way. Automated camera technology can help with capturing pictures and so making a positive identification of the invader.

Can mice see?

Mice are nocturnal and so don’t have a strong sense of sight they are also colour blind; but they have a strong sense of taste and smell, they use their whiskers and guard hairs for guidance when moving around.

Can you get black mice?

There are many species of mice but you will not commonly see a black mouse in the UK.

Can you hear mice?

You may hear mice scratching or gnawing in their surroundings or scurrying around if they are in your property.

Do mice like cheese?

Despite the cartoons and many illustrations, this is a miss-conception. When it comes to setting a mouse trap with bait, mice would rather feast on other things such as peanut butter and chocolate – it is usually best to use anything that they have selected to eat from the local environment, which could even be chips and peas, considering the higher moisture content.

Do rats eat mice?

Rats can hunt and kill mice, this behaviour is called Muricide. However it is rare to have mice and rats living in the same location as rats are more dominant.  If they should be present within the same property, mice will generally climb and nest in higher locations than rats will access.

Are mice nocturnal?

Generally mice are most active at night and so not seen in the daytime; however where the mouse population has out grown the nest they will be seen at anytime of day.  During the colder months they may become bolder as they look for food and warm places to nest or where food sources have been cleaned up and this makes it harder for mice to survive.

Do repellents for mice work?

A common myth is using peppermint oil as a deterrent to mice, there is no evidence to support this. Ultrasonic plug-in devices are also marketed as scaring the resident mice population, again there is little evidence to support this.

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Image by Dan Burton

Dealing with mice and the importance of rodent control in the food industry

Pest control procedures in the food industry cover a wide range of pests but rat and mouse control in food production sites, food handling premises, factories, food storage warehouses, restaurants, hotels, fast food chains, takeaways and catering kitchens is something frequently in the news headlines. 

A mouse infestation on any site can multiply quickly and cause significant damage to reputation, property and equipment and contribute to food spoilage. Food sites are often the perfect place for rodents to take hold, offering food, water, warmth and harbourage; understanding the risks and putting the correct procedures in place for managing pests is key to help minimise risk and all associated costs.

When it comes to control of commensal rodents there is much more to understand than simply putting down bait or traps, PestWise will train you to understand the day to day onsite pest control requirements and develop a comprehensive strategy for food production & hospitality premises using the 90/10 rule – 90% prevention, exclusion, monitoring, proofing and non-chemical options and 10% using pest control rodenticides.

This multi-point approach ensures best practice for stewardship in the safe use of rodenticides, demonstrates environmental protection and also take into consideration regulations such as the Food Safety Act 1990 and Food Hygiene Regulations 2005 and compliance food supply chain SOP (what is this?  requirements implemented by auditing standards such as British Retail Consortium, major Supermarkets, including Tesco, Marks and Spencer, Sainsbury as well as farm assurance schemes such as Red Tractor and Freedom Foods.

It’s important to remember that just having a pest control contractor taking care of pest control on your premises does not automatically cover the proprietor for due diligence. Responsibility is placed on everyone involved to ensure pest control procedures are in place and best pest practices are being followed.

Integrated Pest Management (IPM) and evidence of how it is implemented is a requirement  in food safety legislation and the manufacturing standards guidance for pest prevention by many leading supermarkets and farm assurance schemes.

Often food manufacturing sites are best placed to do their own pest control and not use the services of a pest control contractor, PestWise offer a range of pest control training courses including an online (e-learning) rodenticide course for mouse bait or mouse poison licence (Campaign for Responsible Rodenticide Use (CRRU) certificate) we recommend this course is completed in conjunction with our rodent control in food production or on farm control of rats and mice courses for a more comprehensive approach to rodent prevention and control.

If you are looking for a local pest control company to take care of mouse extermination we can advise on either independent pest controllers or pest control contractors in your area; we also offer independent contractor management and independent ‘field biologist’ audits (farm assurance audits) and reporting.

For further information regarding pest control in food production get in touch

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