Field Notes D.A. Bell May 6, 1990 At Treasure Island, Bnfo. Booth & Museum, just outside entrance to the naval base (gate). SF Co., CA 07:00 - Falcon sitting on catwalk (traveling apparatus) @ SE side, just E of Suspension Tower 5 (the first tower E of Central Cement Anchorage of Bridge. David Gregoire saw this bird first appear at the catwalk @ 06:37. He watched the bridge from 06:00-06:50. The bird may have eaten something at a cache. 07:12 - Walked over ~3' along catwalk (falcon), still on SE side. 07:20 - Falcon out of view, but possible head movement visible - fleeing? 07:45 - Falcon now completely visible. 08:00 - Preening. 08:40 - Falcon stretched, flapped wings, then took off. Flew under bridge to N side, and along bridge at road level to the west, at least as far as the cement anchorage. I lost sight of it. But, turned scope back to At Tower 5. Then the falcon appeared, flew up into the center portion of the grilles, east side of Tower 5, below road. About 30 secs. later another bird came out of some area. Actually looked smaller, it flew up to nearby catwalk, but would not see it. So I may have been watching the F all morning, and she just went back to nest site to relieve incubating F. 08:50: F on SE corner of N- catwalk.