I just saw a bat! Hey, there is another! I wonder if we have them living in the house? How do I know if I do?
Our local bat species are relatively small, almost like mice with wings. They can pass through very small openings; and they prefer to enter buildings at points that are very high off the ground. Few, if any other species are likely to leave this type of “calling card”. This dropping is a little larger than a grain of rice and is attached to the outside of a brick wall. This usually happens as the bats are coming in for a landing. The trajectory of their approach to the landing site propels the dropping toward the wall. Droppings stuck to the wall or laying on a windowsill are a sure sign that there is a colony entrance somewhere above.
The infamous dirty smear is often a clue to an entrance point of some type. Wildlife rarely “wipes its feet” before it comes inside. Dirt and body oil combine to create this brown smear. If the dirty smear is 30′ off the ground it has to be a species that can either fly or climb. In this case, it was bats. Bats tend to pick very high entry points. This is because they have a “gliding take off” instead of a “power take off” like many bird species that we are more familiar with. This means that instead of flapping their wings hard to gain speed on take off, they prefer a high point to glide off of.
Another excellent clue to a colony in your house is noise. ( Sorry not to have some cool sound bite for this one. Maybe I can come up with something later.) Noises can range from scratching, scurrying types of noises to high pitched metallic sounds. The vocalizations are very distinctive. Big Brown Bats are the number one species of bat seen in homes in this area. Once you hear Big Brown Bats make this noise you will always remember it. Otherwise it is impossible to replicate orally and difficult to describe. To say the least, bats have a radically different vocal and auditory set up from humans.
The appearance of a “small visitor” inside the home, can be another clue to the presence of a colony. Bats do sometimes wander in through doors or windows that are left open. But, often individuals in a colony wander off the “beaten path” and end up in the living areas of homes. Especially, if this occurs in late July or August it is more likely to indicate a colony. This is when the young bats are weaning or have just weaned. Like human young, they don’t always follow the rules; and they tend to wind up in the wrong place at the wrong time. This is not to say that all bats found inside homes are just lost. Bats can transmit Rabies to humans and caution should be practiced in these situations.
Guano piles are a definite indicator of bats roosting in