A short visit to the quarry in Woburn under clear skies, bright sun, light wind, and temp around 24F.  While scanning all around with no peregrines in sight, a streaking bird came in from the west, one of the peregrines, and swooped up in long arc, to the nest ledge.  It spent a bit of time preening.

One thing the peregrine falcon does a lot is preening. A number of hours are spent each day, particularly on the care of feathers.  The preening is in fact a necessity to keep feathers net and clean!