There was an owl hooting outside our house earlier, and it occurred to me that every other bird has a high-pitched call.
Ravens have a croak that could be considered low, but their loud call is a caw that’s higher. I can’t think of another bird with a call nearly as low as owls’.
Search engines are no help, mostly duplicates answering why they hoot. Why are owls’ calls so much lower than other birds?
Lower frequencies travel better through dense areas I think. So birds in dense woods would be lower pitched. This is a massive and probably incorrect guess.
I’ll agree with you here. My knowledge comes from choir teachers telling the boys to shut up because our voices boom through the walls.