Unwanted winter houseguests – rats and mice

The return of winter means you’ll be spending more time in your home, but chances are, you won’t be the only one seeking shelter.

As temperatures drop, some of our most despised house guests – rats and mice – are busy searching for a warmer spot to sleep, and many will find it in a wall cavity, snuggled up in ceiling insulation or curled up behind a fridge. This can be a matter of concern, but there are ways of coping with them other than putting down anti-coagulant poisons, which can harm pets that ingest the poison or the poisoned vermin.


Signs you have rats or mice in your home

As rats and mice possess very similar behaviour, signs of an infestation of either of these rodents are comparable, and either will leave behind a number of telltale signs. These include:

  • Droppings – sizes can vary, but typical rat and mouse droppings between 4 – 20mm long and brown/black in colour
  • Damage – keep an eye out for damage along the bottoms of doors, on wires and near electrical outlets; rats and mice tend to gnaw at these – piercing through wiring or compromising electrical outlets. Many house fires have been a result of this activity
  • Sounds – When it’s quiet (such as at night), keep an ear out for the sounds of gnawing or scratching, particularly in your walls. Rats and mice often hide inside the roof or walls during the day and then scavenge for food at night
  • Smells – Rats and mice give off a distinctive smell that is similar to the scent of ammonia
  • Greasy fur marks – rats and house mice leave dirty black smears along well-travelled routes, particularly ‘loop smears’ where they squeeze under roof joints.


How to stop rats or mice

If you believe you have a rat or mouse problem, then it’s important to do what you can to stop them both for your health and also for your safety.  While there are common solutions such traps or poison, it’s important to be careful with these options. Rat poison is a bait — this works for rodents as well as pets. Also, most times the rats/mice die inside your walls, roof or in other areas that are hard to reach, leaving you with a terrible decomposing stench as a parting gift.

A better option is prevention:  make it harder for them to get inside and remove the incentive for such a move.   Often, even seemingly impossible gaps can be enough for rats or mice to get in from the outsides. If there are any gaps or holes that aren’t actually there for a necessary reason, consider sealing them up. Other entry points – such as downpipes – can be blocked off with mesh.  Pay attention to areas with over hanging tree branches, cables and pipes running up the walls.

A mouse can get through a hole the size of a pencil, while rats can squeeze through a finger-width hole due to having very flexible bones.

First thing all householders should do is check entry points and seal them up.   Use a strong mesh (available from hardware stores) to block holes in areas such as the walls and eaves, rather than chicken wire which simply isn’t strong enough to keep a rat out.  For smaller holes, steel wool can be used as it’s very sharp and they don’t like to gnaw through it, however it’s important to stuff it in quite firmly as a determined rat can still pull it aside.   Repair broken air bricks and holes in outside walls, floorboards or skirting boards; tidy up cupboards and remove nesting material.

You should also make an attempt to take away their food supply. Don’t leave food out on the kitchen counter, and make sure all dry goods and grains in the pantry are stored in sealed, secure containers.

For large infestations, or if rodents simply make you squeamish, consider hiring a professional pest control company.

Coincidentally, this year I got a cat, and it’s also the first year that I haven’t seen any mouse activity in the pantry!


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