Welcome to the forum, Louis!
Acoustic monitoring is one method. I personally don’t get involved with it, but some forum members are deeply knowledgeable about various sound recording devices, and they spend a lot of time identifying sound recordings on iNaturalist.
You can read more about it in this thread: https://forum.inaturalist.org/t/bird-ids-from-passive-acoustic-monitor/
eDNA (Environmental DNA) seems promising, although I guess it requires sophisticated measuring equipment that is not widely available for consumer use at the moment. Also, please note this response from staff:
I don’t have much personal experience with these things, but some forum members do. Hopefully they will chime in!
Please bear in mind that almost all iNaturalist users are NOT on the forum. So you might have better luck identifying these types of observations on iNaturalist, and DMing other people who also identify these types of observations.
By the way, what is your username on iNaturalist? I don’t see an account for louisradtke.