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Seagulls are famous for stealing beach-dwellers' sandwiches, ice creams and chips, and now researchers at the University of Sussex have worked out why. 

New research from the University of Sussex, published today (Wednesday 26 May), has found that this cheeky characteristic is a sign of intelligence, as these birds can learn how to mimic the food choices of humans. 

There are many examples of how animals learn from each other and herring gulls are no exception. Gulls show evidence of this when foraging and extensively rely on learning from their species to source and gather food.   

But recent research has shown that gulls have the behavioural flexibility to also take cues from humans.  

Researchers at the University of Sussex studied how gulls in Brighton can learn and apply the knowledge of what humans are interested in, which is known as ‘stimulus enhancement’. 

Using colour to test the stimulus enhancement theory, the researchers positioned one blue crisp packet and one green crisp packet in the immediate vicinity of both individual and groups of herring gulls along Brighton’s seafront. Nearby, a human experimenter ate from a blue or green crisp packet. The researchers found that the gulls would turn their heads to watch the experimenter and, in most cases, then pecked at the matching crisp packet to attempt to find food. 

The research shows that gulls observe humans and the food options they select, and use that knowledge to determine their own food choices.  

The researchers point out that this behaviour is a sign of intelligence.  

Prof Paul Graham, Professor of Neuroethology at the University of Sussex explains: 
“While we know that animals learn from each other, we rarely see animals learning from a totally different species when it comes to food preferences. 

“This interaction with humans is relatively modern, and what we can see is that gulls have adapted to thrive in urban environments by mimicking human food choices. 

“Gulls didn’t evolve to like chips. Over time they have had to learn to engage with humans in order to source food. It is therefore a sign of intelligence.  

“But gulls may be less likely to steal our food if we focus on reducing litter. That’s because littering increases gulls’ ability to learn about how our different food options and how they taste.” 

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