We have a lovely outdoor area at our house, complete with outdoor setting. We love sitting out there. Unfortunately, when we aren't home, the crows also like to sit out there and leave a lovely reminder of their visit all down the front of our chairs.
A couple of months ago, I got sick of having to clean the chairs every week and I took a tip from the cyclists I see riding around in spring with cable ties sticking out of their helmets and tied some cable ties along the tops of our chairs. Although it doesn't look the most glamorous, we don't have crow droppings on our chairs anymore.