Red-billed quelea
There are more quelea than any other wild bird species in the world: they number over 1.5 billion. Single colonies may have as many as 30 million. Queleas can migrate as far as 2,000 kilometres (1,243 miles). Single flocks can destroy as much as 50 tons of grain a day. Queleas have destroyed over US$22 million of grain in a single year.