Below is a link to an article about this app, which is called WeBIRD.

It " allows anyone with a smartphone and a mysterious bird nearby to
record the bird's call, submit it wirelessly to a server and (after a
few seconds) receive a positive ID on the species of bird tweeting away
within earshot."


http://www.news.wisc.edu/19882


This article was written last October and said the creators of the app
hoped to have it ready in time for Spring migration 2012. Don't know
whether they've succeeded in that or not. But at least you will have a
name to search the Web or the AppStore for.

Jane Hadley