User blog comment:Evans0305/BioShock Infinite gameplay videos/@comment-189.189.207.10-20110614001918/@comment-2250991-20110614010439

It is. They did change the voice in this demo, especially when he originally sounded like a Big Daddy. May be it was too much of an obvious thing, and they figured to change it at the last minute. See my Blog on why BioShock 2 was almost Sea Of Dreams as an example of why there's multiple Big Sisters instead of just one.

I don't know why, but one journalist from ars technica had to use this video of a singing bird automaton in place of an aproved image of Songbird, just to describe an idea of if that bird was huge, terrifying, loud, and steampunk.

http://www.youtube.com/watch?v=kIFZ2QKRVDc

Besides the melody, it might have been used as just an example. Songbird might have a different screeching sound from that.