Merlin Bird ID is described as 'Merlin is fun and easy to use—whether you’re curious about a bird you’ve seen once, trying to identify every bird that comes to your feeder, or planning a birding trip to a new country. The answers are waiting for you with this free field guide app from the renowned Cornell Lab' and is an app in the education & reference category. There are nine alternatives to Merlin Bird ID for a variety of platforms, including iPhone, iPad, Android, F-Droid and Kindle Fire apps. The best Merlin Bird ID alternative is iBird Pro Guide to Birds. It's not free, so if you're looking for a free alternative, you could try Raptor ID or whoBIRD. Other great apps like Merlin Bird ID are iBird Ultimate Guide to Birds, Sibley Birds 2nd Edition, Audubon Bird Guide and eBird.
Merlin is a field guide, meant to help you identify birds. eBird is a citizen science app, meant to report birds you see to help in scientific research.