In 1851,16 house sparrows were released in Brooklyn, reportedly to eat caterpillars; in less than 50 years, they spread
In 1851, about 16 sparrows were released in Brooklyn to eat caterpillars. Within 50 years, they had spread across the US and were crowding out native birds.
We haven't written up this one. Hindustan Times - World News has the full story — the link below goes straight to it.