The sound of a <a href="https://en.wikipedia.org/wiki/Kakapo" class="extiw" title="en:Kakapo">Kakapo</a>'s "booming". In this file, Pitch was increased by 50% (no change in speed), because it seems like most regular speakers aren't able to play these low frequencies.
<a href="//commons.wikimedia.org/wiki/User:Mnolf" title="User:Mnolf">Mnolf</a>
CC BY 2.5
<p>Own work, Recorded on Codfish Island, New Zealand<br></p>
<a href="//commons.wikimedia.org/wiki/File:051226-kakapo-billbooming.ogg" title="File:051226-kakapo-billbooming.ogg">Original File</a>