Steve Moran, the Person Who Took the Photo says the Following:
Steve Moran writes: "I live in New York City, and today I went to take pictures of the WTC's wreckage.
I shot this first picture of the rescue operation, looking south on Greenwich Street. When I got home and previewed my pictures on the computer, I noticed something in the one entitled "Down Greenwich 3" that was not in the scene when I took the photo.
Upon blowing up the questionable image (the second picture), it appeared to me to look like an angel hovering over the pile of debris and the rescuers. It couldn't be a pigeon or a seagull because being behind the building on the right, it would be too large.
Also, we don't have any vultures or pelicans here in NYC