Indeed, the birds are after the moss for their nests and if it is a robin he or she knows that moisture means WORMS as well! If you try the rubber snake or the CDs remember to move them often, once a week at least. Birds catch on and figure things out. That is why the owls don't work. If they don't move then then figure out they are not real. Try fastening the pots to the railing or the table they are on and covering the top of the pots with a bird netting cut into small pieces to anchor the moss down but not look ulgy. The robin will finish her nest soon and hopefully leave your Judith alone. I am sorry,it is very frustrating to spend so much time and energy
on your plants to have them destroyed.