Birds are harmless and pleasant to watch until they decide to roost on or near your window ledge, where they often leave unattractive bird droppings, which can damage paint, plastics and other metals. The birds' constant chirping can be distracting when you are trying to sleep or relax; in addition, birds carry diseases, which can be dangerous to humans, especially the elderly and young children. You can solve these problems by keeping birds off your window ledges.
Remove the bird nest if you find one on the window’s ledge. You may need to do this a number of times before the birds stop building on the window sill.
Purchase a bird spike to install on the ledge. Or, make your own version by cutting coat hanger wire or a similar substance into 6-inch pieces using wire cutters. Bundle six at a time and staple multiple clusters to a board. Bend the wires so that they stand straight up.
Scare the birds with sounds. Use a pellet gun to fire into the air near the ledge. Alternatively, purchase a sonic repellent and mount it near the window, following the instructions on the package. The device broadcasts distress signals that keep birds away. Play it every 10 to 15 seconds as the birds are flying.
Frighten birds with visual scare tactics. Attach a rubber hawk or owl, purchased from a garden specialty store, and mount it to the window, using heavy-duty double-stick tape. Alternately, draw large "eye" shapes on a blown-up balloon with a felt-tip marker and attach it to the window sill.
Leave sticky bird repellent, purchased from a garden specialty store, on the ledge to discourage birds.
Apply shredded newspaper to the ledge because birds tend to avoid the strips of paper.
Attach a board at a 45-degree angle to prevent the bird from perching on the sill; the angle makes it slide off.
Place bird netting or a stretched slinky toy over the ledge to make the surface less attractive to birds.