Both her parents (assuming one of the two primary father-claimants is the father) are US citizens. To have Bahamian citizenship at birth, she would have to have at least one Bahamian citizen parent. Even then, if the other parent was a US citizen, she would have dual citizenship. Very few countries' laws make a person a citizen just by being born there.
http://www.multiplecitizenship.com/wscl/ws_BAHAMAS.html
So we're about the only ones?
Nice.
We need to end the anchor baby issue...but that's a topic for another thread.