I personally have never seen much signs of plumage in roosting areas where I hunt. Most plumage sign around here is in or near dusting sights.
So that being said, droppings from a roost tree is all I ever see. May have roosted there during the 16 hr rain, maybe every night, according to what area you are in, maybe already found you a good spring roosting sight if your birds are not still in their winter pattern.