Picture 1

Panorama of multiple bat call events (50+ seconds).
Several pulse trains and buzz-stop events, all in the space of 1 minute.

Picture 2

First 10 seconds of picture 1.
0712-3b sound

Picture 3

Seconds 14-16.5 of Picture 1.
0712-3c sound

Picture 4

Seconds 33-37 of Picture 1.
0712-3d sound

Picture 5

Seconds 42-45 of Picture 1.
0712-3e sound

Picture 6

Seconds 45-53 of Picture 1.
0712-3f sound

Picture 7

The buzz is such a featureless sound that it is worth a closer look. It is also possible that this is some kind of detector artifact. This is the FFT spectrum on a dB scale. The highest frequency is 16 khz (half the sampling frequency) and the spectrum shows a broad peak around 4 khz. This also matches the (probable) maximum sensitivity of the voice recorder in the audio range but in the ultrasound range (x16) this is beyond the piezo detector's sensitivity peak at 40 khz.