Maybe partly connected to the pitch? When I get too much bird noise, as I said, I turn on a white-noise app on my phone. You can set it for low or high, and at low I can still hear them but high drowns them out.
A few days ago I noticed something that struck me as odd. In the spring at the house I would quite often be awakened early in the morning by bird song. This isn't happening now. No early morning bird song.

Is that springtime early morning singing connected to mating?
I can't imagine wanting to block out bird song, but then for 40 years in the city I haven't heard it anyway.
