Birds As The Ending?

When I first read this, I couldn't understand. How could it be that a book ends with such a non-significant line? Why would Vonnegut not have a big ending? This is what I believed until I analyzed it. The war is over, and Billy's alone. A paragraph before the book is over, we read about birds chirping, but then, “one bird said to Billy Pilgrim, “Poo-too-weet?” (PDF File) What this is doing is leaving a question for both Billy and the reader. I interpreted this as if the bird was asking Billy a question. After all, the Poo-too-weet has a question mark at the end. I started asking myself what this question could mean, and came up to the conclusion that it could mean something like and what's next?, or what are you going to do now? This gave me a whole new thought about the last line. While at first I had just thought that it was a weird way to end the book, it actually has a lot of meaning behind it. I like this ending because it leaves the reader thinking and wondering what will happen next. Figuring this out in a way gave me more interest in the book, and made me want there to be another chapter.