Acorn Woodpecker painting

Acorn Woodpecker

When they next hear its tell tale call or sounds, scientists will be able to tell if it's the Acorn Woodpecker, Melanerpes formicivorus,(offset reproduction of acrylic painting) without a formal sighting.

Photo courtesy of: 
By Bob Hines, United States Fish and Wildlife Service [Public domain], via Wikimedia Commons
From: 
To tell a bird by its song