Hi there! It sounds like you want to know if the Merlin Bird ID app can connect directly to hearing aids via Bluetooth on your Mac running OS X 10.15. Could you tell me a bit more about what you're trying to achieve? For example, are you hoping to hear bird sounds through your hearing aids directly from the app, or is there a different use case?

From what I understand, Merlin Bird ID itself does not have built-in Bluetooth compatibility to connect directly to hearing aids. Users have reported challenges when their hearing aids are connected via Bluetooth to their devices because Merlin's sound identification features may not work properly if Bluetooth audio is active. In some cases, people have to turn off Bluetooth from the hearing aids to use Merlin’s sound ID functionality properly2.

That said, your hearing aid’s compatibility with Bluetooth audio sources generally depends on the hearing aid model and the macOS system, rather than the app itself. Merlin captures audio from your Mac’s microphone or imported audio files for identification rather than streaming directly to Bluetooth hearing aids.

If you want to use Merlin with your hearing aids:

1. You can try using Merlin with your hearing aids disconnected if possible, then listen to the app audio through another method compatible with your aids.
2. Alternatively, check if your hearing aids support connecting to your Mac as Bluetooth audio devices. If they do, the system will route audio appropriately, but Merlin’s bird sound identification may still require the microphone input not to be occupied by Bluetooth audio streaming.
3. You could also try using an external microphone that feeds audio directly into Merlin and listen through your hearing aids separately.

Would you like me to help you test your Mac’s Bluetooth setup with the hearing aids? Or, if you want, I can guide you through Merlin’s audio settings to optimize your experience.

Let me know how you’d like to proceed!