“A tsunami of birds all around us,” confirms Rob Butler, a former senior scientist with the Canadian Wildlife Service in Delta who now works with Bird Studies Canada. “It’s astounding that people don’t see them.”

Gary Langham, director of bird conservation for Audubon California, estimates that three billion birds are flying from their wintering grounds as far south as Argentina to their breeding grounds in Canada and Alaska along four flyways — Pacific, Central, Mississippi, and Atlantic.

“It’s an astonishing figure, hard to get our heads around,” he said. “Think about it, while we’re sleeping at night, all these birds are passing over our roof tops and moving throughout the landscape.”

via A winged tsunami.