It is a jaw-dropping scene worthy of a Hitchcock film. In a video that has gone viral a huge gull stands brazenly in the middle of a street and attempts to swallow a black squirrel whole, the creature’s back legs and fluffy tail hanging out of the bird’s beak as it gulps.
While well known as scavengers, large gulls such as herring gulls and lesser black-backed gulls – two of the species colloquially called seagulls – are perhaps best known for pinching chips and ice-creams from unwary seaside day-trippers.
But the new footage highlights what experts have long known: the birds are far from picky eaters.
“The large gulls are omnivorous. They will eat anything as long as it fits down their throat, and of course as long as it is moderately nutritious,” said Peter Rock, an avian specialist at the University of Bristol, adding just that morning he had witnessed another grisly spectacle.
“I was up on a tall building in Bristol and there was a lesser black-backed gull who had presumably just killed a rat, and it pulled its head off,” he said.
Large gulls, Rock added, regularly kill pigeons, targeting the weakest.
“What they will do is drive them down out of the air and push them into, say, a river … and then they drown them,” he said. “They pluck the feathers away and eat the rest.”
Gulls have even been known to eat their own. “Say for instance there is a road accident and a gull gets killed, there’s some food. However, that is a rare occurrence,” said Rock.
“They know everything that’s going on in the way of food,” he said, adding that their range may be 100km (60 miles) in any direction from where they are breeding.
“For instance, if there is silage making somewhere they know about it. They know when it is happening because they recognise the machinery and they will come down,” he said, noting that the birds feed on small animals including nesting birds and amphibians that have been chopped up.
“Gulls have gizzards, like many birds, and what they do is they eat furiously and quickly. And if there’s stuff in the way, they eat that as well,” Rock said, adding the material is separated in the gizzard. “All the good stuff goes down into the gut and the rest of it turns into a pellet which they cough up.”
Paul Graham, a professor of neuroethology at the University of Sussex, said that eating small creatures was normal behaviour for gulls, but the shift to urban areas may have had an impact.
“They’re probably interacting with a different set of animals, much closer to humans, than might have been [in their] environment within which they evolved,” he said. “But within the environment they evolved, they would have eaten rabbits and small rodents and other mammals, if available. So [it’s] just the natural behaviour is just moved to an area where we see it now.”
Humans may also have had an impact, he said, noting that urban animals such as pigeons and squirrels can be very tame, meaning they may not be aware of the danger a gull could pose.
The latest video might appear gruesome, but Graham encouraged a different view, noting that individual gulls become specialised at foraging different foods, whether that is swooping for chips or downing pigeons.
“I would always try to get people to think it looks barbaric, but think of how smart that animal needed to be to develop the bravery and skill in order to do what it’s done,” he said.
“It’s not easy to tackle an animal that’s really big, so you do need to learn about it and perfect the art. It might be quite horrible, but it is an example of intelligence rather than just brute force.”