I call it, "I don't Care What you are, Get Off My Fence."
My flicker is very sweet. She is shy (she literally plays peek-a-boo with me) but has come to trust me and has let me get as close as 4 feet to her (I stopped there so as not to scare her). I was very surprised to see her react to this sparrow this way. But, then again, given the loner status that she seems to have, it explained a lot. I would love to spend my days with her but I can't. I hope she can make friends with the other birds. ;)