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Since the 1950s, Alberta, Canada has been essentially rat-free. They declared war on the invasive Norway rat, and there are currently no established populations. Any sightings have to be reported — it’s the law! Some rats sneak in via transport links, in vehicles such as trucks and campers or via freight shipments, but they don’t get far.
At two and a-half times the size of New Zealand, Alberta is big, and it shares a land border with British Columbia, Saskatchewan and the United States. So how did they do it? Can we do it here?
The thing you have to understand about Norway rats is that they like to live where people live. So, while people have lived in Alberta for ages, there weren’t many. In fact, the Norway rat didn’t start to invade Alberta until the 1950s. At that point, someone had the bright idea of calling them "an agricultural pest". The initial thought was to create a buffer zone on the Saskatchewan border, but their action plan was so successful that the programme grew. Today, public education is a key strategy alongside maintaining bait stations, making sure places that suit rats are removed, eliminating rat food supplies, rat-proofing buildings and checking every building within 30km of the border.
Alberta still has a native packrat, which continues to live in isolated places. In New Zealand, we have not only the Norway rat but the ship rat and the kiore, or Polynesian rat. All three are quite distinct. Norway rats are the chunkiest of the three, and Predator Free NZ describes them as "stocky suburban swimmers". They are social, which means they like to live in colonies. If you find a rat’s nest, it probably belongs to this species. Ship rats are climbers, and the kiore is the smallest.
Can we get rid of rats? All three?
Yes. Everyone has to do their bit, a concentrated effort from householders to the top levels of council and government. In fact, in principle, we’ve already agreed to do it!
Some bigger, bolder strategies may be needed. Starting at the household level, what can we do to make our own backyards less attractive? Removing water sources is a start. Keeping the section clear of clutter is another step, as these can provide security for rodent racers. They don’t like open spaces. Making sure your house has no entry points is an obvious one, and of course, making sure your compost doesn’t become a rodent condominium. Rat traps — of course! Some people would rather use bait, but I think the less toxins in our environment, the better. However, it does take people power.
All of these things are in our control. But a bigger, bolder strategy — what about this goal? Timaru, the first rat-free city in New Zealand? We could do it here. First, we break the city into zones and then eliminate all the rats currently living rent-free, zone by zone. Finally, we monitor for incoming rats.
Our environment and our businesses will be better off. What would it take? Will you help?
• Predator Free Timaru is a group of passionate locals on a mission to bring back the birds to Timaru by predator control in local backyards and green spaces, and is one of many groups nationwide working towards the Predator Free 2050 vision.