Overview
- University of Exeter researchers tested 61 herring gulls in nine Cornish towns by placing a closed box of chips and playing different sounds.
- With shouting, 10 of 21 gulls flew away compared with 3 of 20 after calm speech, while most birds stayed when hearing robin song.
- All human recordings were set to the same volume, indicating birds distinguished acoustic tone rather than responding to loudness.
- Five men recorded the same phrase for both speaking and shouting, and the peer‑reviewed results were published in Biology Letters.
- Authors urge peaceful deterrence because herring gulls are of conservation concern and note future tests could assess female voices and broader settings.