Do you struggle with hearing the high frequency song of a Black & White Warbler or a Savannah Sparrow? If this is the case you may find this free mobile application helpful (currently available from the Apple store). It translates those high frequencies into a lower pitch. This app was developed by Lang Elliott and is a non-profit effort. It is currently available only on iOS but he is encouraging others to use the open source code to expand the app to Android. For more information go to the Hear Birds Again website - https://hearbirdsagain.org