I had looked it up on line and apparently it was either declaring its boundaries or looking for a mate.
A few years ago a female with its youngster were together overhead for quite a while. I think mom was training it. The call of the youngster was much fainter then moms.
When the kid wandered off Mom began screeching till it came to her. Fascinating.
I wish I could share but words are best I can do.
I miss my rose garden. And envy you yours.
Guess we are close to even.
Love All Life; Thank You For Posting! :)