House Sparrow (IMAGE) University of New South Wales Caption House Sparrows might be small, but with 1.6 billion of them, they're the most populous bird in the world. Credit Corey T. Callaghan Usage Restrictions Photo can only be used with credit and in relation to this story. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.