The main signs of a bat infestation are piles of rice grain-sized droppings and dark urine stains. Ammonia smells, scratching and squeaking at night, or bats around your yard are also common signs.

As bug season fades, bat season begins—and if you’ve got an attic or a chimney, these flying critters could become a real issue. While bats may do you a favor and gobble up those annoying mosquitos ...