Merlin Sound ID is an app that uses your smartphone's recording capabilities to identify the birds singing around you. Users can record bird songs and compare them with the songs and calls in the Merlin database to confirm the species they hear. Currently, it supports 1054 bird species in the US, Canada, Europe, Western Palearctic, Neotropics, and India. Users can contribute to Merlin Sound ID by recording bird songs, uploading them to eBird checklists, and tagging the background bird species heard in the recording. This helps expand the app's coverage to new species and regions.