Ultrasonic environmental audio was recorded in Marrickville, NSW, Australia during a hot summer afternoon. The sound field contains vocalisations from multiple possible bird species, including Noisy Miners, Rainbow Lorikeets, Common Mynas, Australian Magpies, Spotted Doves, and Crested Pigeons. Recording was conducted using a Clippy Ultra XLR ultrasonic microphone with a 20 Hz–110 kHz frequency response, captured via an SSL2+ Mk II audio interface.

The audio was imported into spectral analysis software and transposed downward with temporal expansion to expose ultrasonic and micro-temporal structures. Frequencies above 1.5 kHz were removed to abstract the material further and foreground internal spectral relationships. The resulting sonogram reveals a dense, interconnected lattice of partials and transient events, presented as a visual trace of the sound field’s structural organisation.