Nightjars hide their songs inside the noise of traffic
These secretive predators sing at the exact same low frequency as engine hums, using the drone of the modern world to mask their location from hunting owls.
The European nightjar is a master of disappearing in plain sight, possessing mottled brown feathers that make it invisible against a forest floor. But its most sophisticated trick is acoustic. Male nightjars perform a rhythmic, mechanical trill that sits between 1 and 2 kilohertz, a specific frequency range that perfectly overlaps with the low-frequency rumble of distant car engines and rustling leaves. By singing just a few decibels above this ambient background noise, the bird creates a signal clear enough for a nearby mate to find, but far too muddy for a distant owl or fox to triangulate.