Shell Leavers: I checked on this one today and the cache is indeed missing. While looking I saw a new robbin's nest that had eggs in it. At that point I decided to break off the search. I was being yelled at by mama robbin when I got close to the nest. I walked away and when I got back to the parking lot, I turned around to see mama robbin fly back to the nest. All is well in robbin land. Even if I had a replacement cache in hand I would not have placed it in the tree.
Hopefully someone else will hide a cache nearby.