All sounds are unique in nature. They occur at one time in one place and can’t be replicated. In fact, it is physically impossible for nature to reproduce any phoneme twice in exactly the same manner. ~ Murray Schafer
Soundscape recordings
Female RUFOUS HUMMINGBIRDS AT FEEDER
I think both of the birds seen here (if they are different individuals) are females due to the white tips on their tails, but I’m just learning about these amazing little birds.