Could this really work? Next spring, Mark Berres, a University of Wisconsin–Madison ornithologist, will release an app called WeBird that identifies birds by call. I can’t wait to give it a try in my backyard! In the meantime, though, studying id books seems to be the way to go, so check out our full catalog of bird books here: http://press.princeton.edu/birds/.
UPDATE: Making a top-flight bird call identification app is tougher than it sounds, according to Mark Berres, developer of WeBIRD. While the project did not reach the public in spring of 2012, as Berres hoped, he says the app is on track to a release in time for the North American migration in early 2013. Books still good though: http://press.princeton.edu/birds/.