Frequency Spectrum of Swiftlet' Sounds.

A good friend recommended me a good software for frequency analysis.
So I played a few sounds and here are their results.
Please notice the frequency of each sound, mostly are below 9k hz. except the last one which is a stress sound, its frequency is in a broader range.

An external sound. 1.5k-8k hz.



An internal sound. 1.5k-8k hz.



A colony sound. 0-9k hz.




A stress sound. 2k-13k hz.