In our former home, a female robin built a nest atop my grapevine wreath near the laundry door. When I discovered it and found no eggs, I took it down and placed it upside down on the table beneath the wreath and planned to dispose of it later. By morning, she had flipped the nest over and promptly layed three blue eggs. For the rest of the summer, we used another door to go onto the back porch so as not to disturb the babies. -- Regarding the pooping. When she would come to feed the little ones, she would tap on the behind of one, it would raise its backside and as the baby pooped, she would take the sack of poop and fly off with it dropping it wherever. So the poop you see splattered everywhere, is hers or possibly that of a baby. Needless to say, I am very aware of building of nests.