What is the defining characteristic that makes the Red-billed Quelea notable in the avian world?

Answer

It is the most abundant wild bird in the world

The Red-billed Quelea holds the status of the most abundant wild bird globally, with populations estimated in the hundreds of millions, potentially exceeding a billion.

What is the defining characteristic that makes the Red-billed Quelea notable in the avian world?
birdfaunaOriginquelea