Staring down a seagull is the best way to prevent it from stealing your food.
Seagulls won't steal food if they are being stared at
Glaring at the seaside pests frightens the birds and means they are less likely to pinch your sandwiches and chips.
Professor Paul Graham, an animal behaviour expert at the University of Sussex, said: "Animals that steal are aware of the attention of the individual they are trying to steal from.
"If a bird is in the air and you are worried it might attack, then simply staring at that bird and pointing will stop it coming towards you."
The findings back up a previous study by Exeter University which found that herring gulls nabbed food a lot faster if they weren't being watched.
Researchers placed a bag of chips on the ground and it took the birds 21 seconds longer to start gobbling them up when people were watching.