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?
I think everybody here’s right.
However, that still doesn’t answer the question of how they are so low…
I believe that would require that their “voicebox” be huge, compared with other birds’.
Every bit as much a guess as the others, here,
but a knowledge-based guess, as the others are, too.
Insightful question!
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The syrinx is a birds equivalent of our vocal chords.
From Wikipedia
Addendum from PA Game Commission