Happened on Sunday. Let my dog out in the backyard and heard one of those birds that go tweet TWEET^. I can mimic the sound pretty good with a whistle so I started copying it.
Most of the time I just repeat after the bird doing the call, sometimes I troll them and interrupt them. This time I decided respond after but with the opposite call. So I did a tweet Tweet v. Instead of ending on a high note I ended on a low note.
The bird paused. And kept going after a few seconds. I did the new call another 2-3 times and could hear the bird moving around. Then I switched back to the original call once and stopped. It got so pissed, it was tweeting several short and aggressive tweets. Lol I laughed and went back in because my dog was done pottying.
Edit, I found the birb. Black-Capped Chicadee