OMG OMG!!! Ridiculously exciting! This will teach me never, EVER to walk anywhere without my camera!
So I was walking back to my office from an administrative meeting late in the afternoon, where coincidentally we had just ended the meeting all chatting about the Harvard redtails and my blog with pics of them, and I was saying no, I haven't even seen one in weeks, and...
I had a hawk fly right over my head, by the Faculty Club, and land in a tree across the street. I could tell immediately that it wasn't one of the redtails -- too small, and a banded tail (and the babies with the banded tails aren't even born yet) -- and wasn't a peregrine either (brownish, not grey). I was able to run around and get a look at it from the front, with the sun behind me, and then it flew off over Houghton Library and away.
Just got back to the office and looked it up -- it was an immature Cooper's Hawk! (!!!) I've never seen one before, at all -- and apparently we've got one in Cambridge!
http://www.allaboutbirds.org/guide/Coopers_Hawk/id (Actually, I'm trying to decide if it was a Coopers or a Sharp-Shinned. I THINK its tail was more rounded with a white band on the end, which points more towards Coopers. It looked EXACTLY like the pic of the immature Coopers at far left at the bottom of the page linked here.)
EXCITING!