The Incredible Call of the Southern Cassowary

The Southern Cassowary (Casuarius casuarius) is a large flightless bird found in the wet tropics of Australia and in parts of Papua New Guinea. The call of the cassowary is one of the lowest frequency sounds made by any bird. More of a non-vocal sound than a ‘call’, cassowaries create this booming rumble from deep within. With head tilted down toward the ground, its whole body shudders as the sound is produced. While scientists are not sure exactly what internal mechanism creates the sound, it is clear from watching a cassowary that it uses its body as an amplifier in some way.

Going to as low as 24Hz, these deep calls are bordering on ‘infrasound’. Low-frequency sounds carry a significant distance and are no doubt an effective way for cassowaries to communicate in dense rainforest.

Cassowary sounds

I recorded this first sample from a captive bird in a wildlife park near Sydney, Australia. Hearing the call up close was an a little unnerving – I ‘felt’ the sound as much as I heard it. It sounded more like the growl of a large mammal than a bird!

To hear the cassowary’s deep vibrating booms in the example below, you’ll need decent speakers or headphones – speakers on a mobile device or laptop will not transmit these frequencies.

The following video contains a few different examples of Southern Cassowary sounds: