If you don't want seagulls to steal your food, then shout at them.
That's according to Researchers at the University of Exeter.
They examined different ways to prevent the birds from approaching a box of chips on the ground.
Birdsong and a recording of a male voice shouting 'No, stay away, that's my food' were played to 61 herring gulls across 9 seaside towns in Cornwall.
Almost half of the seagulls flew away within a minute of being exposed to the shouting voice.
But 70 per cent of the gulls stayed near the food when the birdsong was playing.
So the next time you're in Eyre Square, or down at Spanish Arch, and your food is under threat - consider roaring.