I'm sorry, have experienced the same, and have no solution. Eventually that f*cking mockingbird just moved on after weeks just outside my window.

But now something is driving me crazy. There was a movie late 90's or early 2000's... a comedy - where one of the characters was having this exact problem. It was something like Dumb and Dumber or Something About Mary. I thought the actress playing that character was Janeane Garofalo but I could be wrong and don't see an obvious movie of hers on IMDB. Basically a mockingbird outside her window was keeping her from sleeping and driving her insane. If anyone knows what that movie was, please tell me.