The weather out here today was absolutely beautiful so Ben and I enjoyed a 20 mile ride out in the country.

At around mile 12, I started hearing birds chirping - kind of in sequence, sort of a 'whistling' sound.......but this sound kept following me.
It was really starting to irritate me ....

I started to think of Alfred Hitchcock's, "The Birds", and as well, Tippy Hedren.... The sound was that piercing!
This noise happens when I am pedaling (only) -- so, I had 8 more miles of pedaling to go before we got to the car to get the spray for the chain....

This seemed to help about 90%, but I didn't take it for a long enough ride to really see.
Does anyone have an idea as to what this might be?

Thanks a lot!

Have a great evening.

Denise