THEY stalk the waterfronts and seaside towns of Scotland, waiting and watching with a beady eye for the unwary to reach for a chip or let their concentration momentarily stray from their ice-cream.
And now scientists say that seagulls aren't just opportunistic food thieves, but actually prefer to eat things that have been handled by humans.
Just as dogs and cats get excited when they see their dinner coming, gulls have learned that people know where fine dining can be found, and have developed a taste for it themselves.
However, it appears the flying scavengers can be deterred by a good stare, although will still try for a sneaky bite if someone's back is turned.
Gulls are flocking to towns
A study of the eating habits of seagulls which terrorise coastal towns has revealed startling insights into how the airborne opportunists source their sustenance.
In the experiment, herring gulls were presented with two identical food items - one of which they had already seen a person holding.
And when they got the chance, the birds pecked more often at the food which had been handled, suggesting they use human actions when deciding what to eat.
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Lead author Madeleine Goumas, a zoologytudent of the Centre for Ecology and Conservation at the University of Exeter, said: "I presented individual gulls with two identical food objects, and only handled one of them.
"When I moved away I could see which item, if any, the gull approached. We found the majority of gulls pecked at the item I had handled.
"This implies they are using human cues when making foraging decisions in urban areas."
Peckish seagulls have become a blight on towns from Aberdeen to Ayrshire, with local authorities perplexed about what to do about the flying menace.
Seagulls like to eat what people eat.
Last year Aberdeen City Council it would be deploying a hawk in the city centre from next month to prevent the birds from nesting on buildings, and while Dumfries and Galloway spent £263,000 between 2009 and 2016 on control measures for gulls.
Aberdeen North's SNP MP Kirsty Blackman previously revealed that the birds were terrorising her constituents. "Look up internet memes on seagulls - the Aberdeen seagull is the size of a large dog. It is absolutely ginormous and it regularly gets mentioned," she said.
A debate in the House of Commons last year heard how seaside towns are facing "gull wars" as the birds start breeding again.
READ MORE: Seagull caught on camera swallowing starling whole
Conservative Anne-Marie Trevelyan, who represents Berwick-upon-Tweed, said locals "are having to take the law into their own hands to deal with these really difficult and aggressive birds", with some people "wandering the streets of Berwick with firearms".
But Ms Goumas said the study, published in the Royal Society journal Open Science, offers hope of thwarting the growing problem.
Last year her team reported the birds were put off from approaching food when a human looked them straight in the eye.
They put a bag of chips down on the ground as bait, and recorded the birds' waiting times.
More than a third went for the snack, nd it took them 21 seconds longer, on average, than when the person looked away.
Ms Goumas said: "We could potentially do things to change our behaviour to stop this association being used and prevent gulls from eating the food we are dropping."
The unique experiment was carried out with Ms Goumas approaching individual gulls and putting two buckets on the ground in front of them, each covering a wrapped flapjack.
The buckets were then removed, and the scientist picked up one of the flapjacks, handled it for 20 seconds, and then put it back down on the ground.
In total, 38 gulls were tested - with 24 pecking at one of the flapjacks. In 19 of these cases (79%), they chose the one that had been handled.
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Added senior author Dr Laura Kelley: "Our findings suggest gulls are more likely to approach food they have seen people drop or put down, so they may associate areas where people are eating with an easy meal.
"This highlights the importance of disposing of food waste properly, as inadvertently feeding gulls reinforces these associations.
"Herring gulls have a generalist diet that typically includes fish and invertebrates, but they will also consume food found in landfill sites and household waste."
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