Birdsong as it fades out

Listening to ecosystems is different from seeing them. But the diversity loss hits as painfully

Where did humanity get music from? Likely from natural sounds and rhythms, which were once our only acoustic inspiration, and which remain the baseline for what we hear in today’s remaining wild places. This is the theory expanded in The Great Animal Orchestra by Bernie Krause, naturalist and Apocalypse Now musician. He’s been recording such sounds since the 70s, but 70% of his archive is already historical, as the original habitats have radically changed. This is the poignancy of using natural soundscapes for biodiversity monitoring today: One is recording a disappearing world.  This is true too of the scientists and nature enthusiasts who are together creating “a large-scale crowd-sourced annotated acoustic dataset of Indian fauna”. On top of the catalogs of our forests, tigers, birds, they’re building a digital memory of what all these sounds like. 

In a preprint paper about the vocalisation of 518 species across 25 states and Union Territories, the authors admit an “avifauna” bias in the dataset. In future iterations, they hope to cover wider acoustic diversity, including insects, bats, marine and freshwater fauna. Crowd-sourcing is crucial to this task – going beyond profs carrying expensive equipment. But even with birds alone, many challenges for sorting the data have to be overcome. For example, several species are less vocal outside the breeding season, so the timing of recordings needs to be standardised. What’s key is that acoustic indices can indeed predict avian diversity. This is how a Western Ghats study, for example, has found that species richness is lower in tea plantations, than among shade-grown crops.

Finally, what we casually call “birdsong” is not one thing. There are alarm calls, contact calls, begging calls, territorial songs, courtship songs. Not all birds even “sing”. Storks clap their bills, woodpeckers drum on trees, some birds use wingbeats. All this behaviour passes on through both biology and culture. When humans change bird habitats, they change bird culture. 

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