Bat Watching 101
Bats are fascinating creatures to watch as they twist and turn and dash about the sky catching insects. So, how can you maximize your viewing potential?
Many species start hunting before dark and are clearly visible against the twilight sky. So start before sunset and find a place that has something that bats need -- food or water or both. Bat viewing near lakes is usually very successful. Not only are these little mammals coming in for a drink (they drink on the wing) but many insects are found there. Little Brown Myotis and Yuma Myotis prefer to hunt over water. Insects are also found in foliage. Big Brown Bats are often seen hunting along the margins of wooded areas.
Street lights and porch lights provide a smorgasbord for many species of bats because they attract insects. Many people know to sit quietly on a porch at night where they can actually time the repeated flights of a single bat doing a "milk run" in the lighted area.
Bat watching is a summer activity -- all our bats eat insects, typically several hundred each night. In winter insects become very scarce, so our bats must either migrate to a warm region or hibernate. In our area we have species which do each.
Bat roosts may be in tree hollows, buildings, bridges, culverts, overpasses, caves, old mines and under piers. If you are lucky enough to know where a roost is, you can watch bats emerge at dusk. Be careful not to disturb the bats in their roost. Many of our rarer species will leave a roost if humans enter.
One of the best ways to observe bats is with a "bat detector" This is a small (but expensive) piece of electronic equipment about the size of a transistor radio. It can translate the bat's echolocation calls into audible sounds so that you can listen to the bat as it hunts. When a flying insect is located, the bat needs additional information to zero in on its prey. So, it calls faster and faster until it sounds like a buzz or zipper. This is called a "feeding buzz" and is clearly audible with these detectors.
Detectors also allow you to make an educated guess as to what species of bat is flying by. Just as birds may have distinctive calls, so may bats.
Good bat hunting is found each summer in Seattle around Green Lake Park and in Tacoma at Point Defiance Park. Bats Northwest leads bat walks throughout the summer in which we discuss our native bats, answer questions and listen with our bat detectors. Call 206.256.0406 for details.