Birds are pooping all over my deck and patio. Is bird poop dangerous?

Bird poop (or guano) is usually more of a nuisance than an actual health risk, though there can be a risk of disease transmission, especially for those with weakened immune systems.  Clean up with soap and hot water whenever you have contact with bird droppings. In places where you are concerned about guano from nesting or roosting, you may be able to block access to those areas with fishing line, netting or a block of wood or Styrofoam material.  Discourage perching by installing visual deterrents like shiny pinwheels, mylar flash tape, or commercially-available bird balloons.  Plastic owls with "bobble" heads that move  with wind can work in many situations.  To clean up small messes caused by birds, use water from a hose; or for larger messes, follow the guidelines on the Internet Center for Wildlife Damage Management website--which include using a mask or other breathing protection, protective clothing, and bleach or detergent.  For more information on diseases spread by bird droppings, see various resource page at the Centers for Disease Control.