When European settlers arrived in New Zealand in the 1800s, some decided to bring rabbits to enable hunting.
That brought with it a second order consequence – rabbits multiply. Really quickly. Soon, they became pests in the fields.
To fix this, a few came up with the bright idea of bringing stoats to hunt rabbits.
And this is where the second order consequences become really sad.
New Zealand evolved without predatory mammals. So as a result, the birds developed mammalian tendencies, and many birds just stopped flying. They found plenty of food on the ground and flying is energy intensive. So unless you really need to fly, why bother?
As a result, many of them stayed on the ground with a typical tendency to either be curious about anything that approaches them. Or to freeze when they are scared (since their predators were in the sky).
This sadly meant that they were easy prey for stoats – who ended up hunting many, many more native birds than they did rabbits.
This has resulted in multiple mass extinction events of native birds in New Zealand.
Over the past 100 years, there have been many attempts at reducing the stoat population. The New Zealand government even has a goal of removing all stoats and non-native predators by 2050 to save the remaining native birds whose populations have been decimated.
Attempts at progress right now include setting up stoat traps all over the place that aim to instantly kill stoats as soon as they are trapped.
But there’s no end in sight – especially because there is a similar story with Possums from Australia. More innovative solutions are going to be needed.
It is worth noting here that the stoats (and possums) are not at fault. They’re just trying to survive in this place that they have come to regard as home too. However, they were brought by human settlers who didn’t think through the second and third order consequences of their actions.
And now both of these are decimating native birds who play a critical role in the circle of life and the ecosystems in New Zealand.
This story is a reminder that there’s so little we understand about nature and ecosystems.
If there’s any hope, it is that we are capable of learning from our thoughtless mistakes (of which there are many).
Hopefully we’ll be able to do that in New Zealand and beyond.
A Learning a Day 