Knock! Knock! Who's there?

Knock! Knock! ....... "Who's there?" I yelled, as I came running down the stairs. I figured it was a neighbor knocking at my back door. To my surprise I saw a duck pecking at my sliding glass patio door. I think it's the same duck that came to my patio last spring. He must be hungry and looking for food. As much as I want to feed him, I decided not to. If I do feed the duck, he will bring his whole entire family and my patio will be a mess, if you know what I mean. I told the poor duck to leave, so he waddled on out off my patio. A little while later I heard a faint knocking sound again. I looked outside and sure enough that same duck was pecking on my neighbors glass door, but no one was home. It might have been my imagination, but I thought I heard the duck yell "Aflac!" LOL!