There Is A Bird On Your Head! (By Mo Willems)

Cute book! It is an easy reader for young children, but could also be used in elementary classrooms to talk about communication. It has been awarded the Theodore Seuss Geisel award.

Elephant senses he has a bird on his head and Piggie confirms it is true. Elephant clearly isn't happy about this, but never actually asks the bird (and others that come along) to get off until the end. In the end he simply asks them to go and the little birds say, "No problem" and they find a new place to rest...on Piggie's head!

The summary at Good Reads says:

Gerald is careful. Piggie is not.
Piggie cannot help smiling. Gerald can.
Gerald worries so that Piggie does not have to.
Gerald and Piggie are best friends.
In There Is a Bird On My Head , Gerald discovers that there is something worse than a bird on your head--two birds on your head Can Piggie help her best friend?

 
Mo Willems has a whole series of Elephant and Piggie books. One of my favorite things I read about him is that he worked for Sesame Street from 1993 to 2002, but he has done a lot more than that!