The definition of a pest, according to the dictionary is this:
A destructive insect or other animal that attacks crops, food, livestock, etc
Crops, food, and livestock are examples of resources we depend on for our survival. 'Pest' is a designation we latch onto other lifeforms (even human beings) when they compromise our survival or comfort. My interpretation is that a pest is the symptom of a negative interaction between non-human species and human beings.
No animal is born a pest. 'Pest' isn't some type of genus. A rat is a rat. A possum is a possum. A rat in the McKenzie high country that has never negatively affected a human being, is just a rat. That same rat's cousin lurking around the sewers in Auckland central, would be classed a 'pest' - because it may spread disease. I.e have a negative effect on humans. Humans being the key word here.
Therefore, it's contexual. Pest control has a place. When the removal of problem animals has a direct, positive influence on OUR lives, it makes sense. Farmers culling deer, rabbits etc. Possums and stoats eradicated from orchards or bird sanctuaries. Snails from your vegetable garden. It's logical.
But are rats which attack birds nests in the middle of the Fiordland wilderness (rats and birds nobody will ever be directly affected by or encounter) 'pests'? Since when did the interaction between other animals concern us or require our intervention? Of course, I do not think that is the underlying reason. It's just an excuse to justify unethical practices used to boost our tourism industry.
I'd argue they are not pests at all, but rather an invaluable resource to an industry which is rapidly gaining momentum in New Zealand.
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