This page last updated April 26, 2004
Once you record a sequence of calls from a bat, you now have to do something with those calls. The problem with real-time recording systems is that they produce files that are quite large, so you need to break the files down into smaller pieces so that they can be analyzed more easily.
Below is a two-second sequence of calls recorded from a big brown bat (E. fuscus).
The calls are clearly visible on the screen, but the time to manually select and save each of these calls would be prohibitive. I use computer programs that detect the increases in amplitude (visible in the top part of the graph) to determine where a call has been recorded. It then takes that segment of the file, copies all the information until the sound level drops back below the ambient level, and saves that information to a new file. That information will correspond to an individual call. Here's an illustration showing where the software would separate the calls:
You can see that 10 different calls will be extracted from this segment. Below is an illustration of call #2:
Each of these calls is saved into its own file with a unique name, along with the time that the call occurred relative to the beginning of the call. After extraction, I can have the computer analyze the calls and save that data. Click the link below to see how the calls are analyzed.
 |
To learn more, return to my main page and click on the links...