This 5 March 2020 video from England says about itself:
Seagulls are more likely to pick up food that humans have handled
Seagulls prefer to approach food that has been handled by people, suggesting that the birds may use human cues to find a meal.
Madeleine Goumas at the University of Exeter, UK, says the idea for her research came from observing how seagulls acted around humans. “Are they just looking for food, or are they noticing what people are doing and picking up on their cues?” she says.
Read more here.
The video shows a herring gull.