A bird that I called a pest this summer was a Corncrake and a couple of his pals. I would never, ever harm one intentionally, but this three were certainly pests.
I was camping at a campsite on Tiree in June, when hubby and I were putting up the tent we heard a gentle "Crex Crex" type call. We were both so pleased to be sharing our campsite with a Corncrake and soon realised there were three around us.
However later that night, just as we were dropping of to sleep, the three of them started, one mere feet from our tent - "CREX CREX CREX CREX"
From about 11pm to 4am, they didn't seem to even stop to breathe, we didn't sleep during that time that night or the following night. Thankfully after 2 nights we moved to a hostel with friends, so were able to get some sleep.
But the biggest reason I called them pests was because even though they were so close, we never even got the slightest glimpse of them, they stayed completely hidden.