I’ve been really impressed with the Merlin App for Android Sound ID.
There have been a few birds that I have not been able to spot or identify visually but using Sound ID I can quickly pull up and confirm which bird I’m hearing.
The Pacific Wren has an amazing song and I noticed for years the calls but I’ve still yet to see one.
Also particular impressive was it’s recognition of the Stellar’s Jay non-screechy vocalizations.