Mice and rats can make great pets, but they are terrible pests to have running around the home.

I hate killing the cute little mice we get around here, but letting them run rampant presents hygiene and safety issues. Mice and rats are well known for chewing through electrical wires, consequently starting fires and wreaking all sorts of structural havoc. Finding mouse poop in the kitchen isn’t a particularly appealing occurrence either.

There are wider environmental issues too. In many places, house mice are not a native species. They compete for food to the detriment of other animals. In Australia, mouse plagues have stripped areas bare of food sources.

Most rodenticides you buy in the supermarket contain rather nasty ingredients including  Warfarin, Bromadioline or Brodifacoum. These chemicals are brutal on the animals. They die horrible deaths through internal bleeding and it can take anywhere from 3 – 10 days for death to occur.

Aside from the cruelty aspect to the rodent; given the length of time it takes for the animal to die, they tend to continue feeding on the bait for a while and the poison builds up in their system. As they become weaker, they become easy prey for other animals. Animals such as dogs, cats and birds of prey that feed on the poisoned rodents are then poisoned themselves. If it doesn’t kill the predator outright, the poison remains in their system for quite some time – so there’s greater chance of the next rodenticide affected mouse or rat they consume finishing the job.

The other issue is one of tolerance – rats and mice are hardy animals that breed regularly during their short life spans. Some Warfarin resistant strains of rats and mice are have been observed, so more of the chemical needs to be used. Other animals haven’t developed this tolerance, so chances of survival should they consume a poisoned rodent become even slimmer.

I’d hate to think how much “collateral damage” is wreaked upon the environment each year by these poisons. To top it all off, rodenticides are deadly in aquatic environments too – so never flush old poison down the drain.

While chemical rodenticides such as the above do have their place at times, it’s a case of prevention is better than cure. Here’s some earth friendly rodent control tips:

– I’ve noticed that one of the favorite points of entry for rodents in brick homes, mice in particular, is through the expansion joints between the bricks. There are purpose made products out there for sealing these gaps, but I just use crumpled up chicken wire to shove in the joints. The chicken wire still allows the brick to expand. When the brick contracts, it leaves a bit of a gap, but the wire ends discourage rodents from entering.

– All gaps leading into your house should be sealed. Steel or copper wool and scourers are useful in tricky places.

– Compost bins are unfortunately a drawcard for rodents. Quite a few times I’ve lifted the lid on ours to find a mouse looking up at me as if to say “am I wearing something of yours buddy!?”. We have cute but arrogant mice here :). Where possible, get your compost bin off the ground, but drill small holes in the base so moisture can still drain away. Avoid putting food scraps into a compost bin – a worm farm is a better option.

– Keep your yard as clear as possible of piles of debris and regularly check under logs and rocks for signs of nesting. Disturbing the area regularly will discourage rodents from establishing themselves, and in the process you can also get rid of pesky snails and slugs.

– Mice need very little food to survive, so regular sweeping of your kitchen area will help deprive them of sustenance and a reason to hang around.

– If you’re in a rat prone area, use metal garbage cans instead of plastic ones – rats will attempt to chew through the plastic bins.

– Fallen fruit should be removed from under trees.

– If you’re building a new house or considering reinsulating your current home, consider recycled cellulose fiber – it’s a highly effective “green” insulating material and the (safe) chemicals it’s treated with discourage rodents from nesting in it.

– Rats and mice love seed, so if you do have a bird feeder, try to keep it as far away from the house as possible and in the open with nothing that could be used as a rodent hideout nearby.

– With your recycling items, ensure cans and soda bottles are stored in sealed containers or bins

– Something I found out recently – mice love to eat soap; so store any soap you keep outside in a container. I had a cake of it in my shed and it seems it was a tasty feast for them. They’ll also eat leather and cloth if other food sources aren’t available.

– If your cats and dogs “graze” don’t leave their pet food out for long periods; particularly overnight.

– Speak to your local pest control company about alternative trapping and repelling methods such as ultra-sound and electric zappers (update: read my Victor Multi-Kill Electronic Mouse Trap review)

– I’ve read that rodenticide products containing Calciferol (vitamin D), cholecalciferol (vitamin D3) and ergocalciferol (vitamin D2) are less likely to cause secondary poisoning of other animals. It’s still deadly to many animals if consumed, so treat it with the same care as you would the other poison and it should be placed in tamper proof bait stations.

– If you use snap traps, peanut butter is a great bait. You can also put the trap inside a paper bag so you don’t need to handle the animal once it’s been trapped. Be sure to place the traps where you know other small animals won’t get to it.

It’s recommended not to reuse a snap trap as the scent of the dead mouse or rat will repel other rodents. Given that, it’s a little expensive and wasteful having to buy a trap each time, but if you choose to do so, buy the ones made of wood, not plastic.

– Live traps can be re-used; in fact, by leaving a single mouse in a live trap, it will attract others (not the case with rats though). How to humanely dispose of the live mice is another issue. Ideas anyone?

– Get a dog. Not a cat, a dog. A terrier to be precise. Fox/Jack Russell terriers are the best mousers and ratters around. Our 13 year old terrier moves about very slowly due to her age, until she gets wind of a mouse – then she becomes as agile as our 5 year old foxie. Terriers do not play with rodents like cats will, they kill them extraordinarily quickly; so it’s a little more humane I guess.

If there’s multiple mice, a foxie will kill one and immediately move onto the next – I’ve never observed our dogs actually eating one. Fox terriers can be trained to leave other animals alone – for instance, our dogs become super assassins with mice, but they let birds eat from their food bowls. They are great companions and watchdogs – the mousing is just a fringe benefit :). Cats on the other hand are more indiscriminate killers; cause massive problems in relation to native wildlife and it’s my understanding that they are pretty much useless when it comes to rats.

I thought I’d finish off  this article with some rodent related trivia:

– Mice can leap up to 1 foot vertically and will jump against a vertical surface to use it as a launching pad to get extra height. A rat can jump up to 3 feet.

– Mice can produce up to 50 young a year.

– A mouse can become pregnant again within 2 days of having given birth to a litter.

– Warfarin is also used as a blood thinning medication for humans – in much smaller quantities of course.

– A mouse can squeeze through a space less than a quarter inch wide, rats only need a half inch (depending on the species)

– Rats memorize their environment by body and muscle movement

– A rat’s front teeth never stop growing, hence the need to continually gnaw

– A single rat creates 25,000 droppings in a year

Pests? Most definitely, but mice are just so darned cute and I admire their resilience and adaptability; I hate having to kill them. It’s a shame we can’t all live together in harmony :).