Better get them gulls off the roof if you have asphalt shingles. Gull poop'l eat right through em. I had to reshingle my baby barn due to pidgeon droppings. I am also reminded of when I worked on an airport runway in Churchill Falls, Labrador where the gulls used to gorge themselves on blueberries by the side of the strip and then sit on the warm pavement until they had digested the berries. Had to repave the strip prematurely because of the damage.