Birdsong is a sound which most people find reassuring. There is a reason for that. Over hundreds of thousands of years we’ve learned that when the birds are singing, things are safe. It’s when they stop you need to be worried.

Treasure links a commonplace comfort—hearing birds sing—to an evolutionary reading of sound as information. Birdsong functions as an ambient “all clear”: if small, vulnerable animals are vocalizing, the immediate environment is likely free of predators or other threats. The flip side is the sudden absence of birdsong, which can signal disturbance and heighten vigilance. In the broader spirit of Treasure’s work on listening and soundscapes, the remark underscores that humans continuously (often unconsciously) interpret acoustic cues to assess safety, mood, and context—suggesting that what we hear shapes how we feel and behave, not merely what we think.