P, bass can change color in a matter of hours, heck even minutes to match surroundings. The nights are getting longer and days shorter and I am sure you are witneesing the beginning. Those fish might have been lounging over off Napatree or the sand flats off of Stonington and now that the water temps are ever so slightly receding, they could make there way back east around Watch Hill to seek and destroy. There have been a few glimpses of life the last couple nights on the south shore of the Cape up my way so the natural signals, as you suggest, could certainly be ramping up and starting to affect your fav gamefish. Go get 'em!
