If you are in your attic and you notice a pile of droppings like the one pictured above you most likely have bats. It is very easy to tell if the droppings are that of a bat or rodent such as flying squirrels. Bat droppings will turn to powder if they are pressed on. Squirrel droppings will smear if fresh or be hard if older. If the bat droppings are examined closely you will notice bits of insect exoskeleton in them. If you spot a pile look up that is where the bats are roosting, or the entrance exit point is located. Caution do not assume that if you do not see bats, that it is OK to ciel up the hole you may have found. Bats have a very good sense of hearing, and may have hidden under the insulation or behind of wall when detecting you entering the attic. Even as a professional bat control expert many times I do not locate the bats themselves. They are very fast even when crawling.
I have personally witnessed the aftermath of home owner bat removals that have gone wrong. A trapped bat will follow air currents in an attempt to escape. Often these currants will bring the trapped bat into the living quarters of the home. One home ended having 15 bats flying around the living room. The other possibility with a misguided bat removal is dead bats, and depending on the size of the colony the smell is horrible. Imagine letting ten pounds of meat rot inside your walls.
Bat removals and exclusions are best left to professional wildlife control companies. A recent trend is pest control companies getting into bat removals. Pest control (bugs experts) are not the same as Nuisance Wildlife Control Operators. Pest control companies tend to treat bats the same as they do insect control. This is a huge mistake, bat removals take a lot longer to do, and very close attention to detail must be used. I am not telling you that you have to use us for your bat infestation. I am just warning you that wildlife control companies are the true experts in this field.