Active Survey
An active survey involves monitoring bats while you are present (stationary/walking/driving) while you receive some real-time output (visual or auditory) from the detector. (advantages and disadvantages chart)
Alternation
Where the characteristic frequency of the pulse alternates between pulses. Typical of some bat genera (eg. Chalinolobus spp.)
Amplitude
Refers to the volume or loudness of a call; e.g. ‘maximum amplitude’ means ‘loudest’.
Atmospheric attenuation
Atmospheric attenuation is the reduction in sound intensity as it travels through the atmosphere. Factors like distance, humidity, temperature, and air pressure contribute to the gradual weakening of sound waves.
Bandwidth
The total frequency spread of the call from maximum (Fmax) to minimum frequency (Fmin); refers to the dominant harmonic when multiple harmonics present.
Biophysical attenuation
Biophysical attenuation occurs when objects in the environment absorb or reflect sound waves before they reach the detector, resulting in a decrease in sound intensity or a change in its path.
Body
The flattest and often loudest part of the call.
Call
A single pulse of sound made by a bat.
Call sequence
A series of pulses from a bat recorded in succession by the detector.
Call shape
Refers to the two-dimensional shape of the call when displayed on a time x frequency chart. Generally described as being either constant frequency (CF), frequency modulated (FM) or quasi-constant frequency (qCF) calls.