In 1867, Canterbury released 40 house sparrows to eat crop pests; within 15 years New Zealand was poisoning the birds and paying bounties after they began stripping grain crops

• The Canterbury Acclimatisation Society liberated 40 sparrows in 1867.
• (Picture: Birds of the world)The house sparrow was brought to New Zealand in 1867 to help farmers deal with crop-eating insects, but the small bird soon became a problem of its own.
• Within a few years, while it grew in numbers, it also began damaging crops, leading farmers and authorities to turn against the species.