For some, a day out at the beach can be more than hindered by seagulls, or gulls if we’re going to be ornithologically correct.
The incessant squawking, dive-bombing, and worst of all stealing food can really put one off one’s chips. But why, of all the species of birds found near the sea, do gulls have such a terrible reputation for snatching not just chips, but even ice creams and sandwiches out of unsuspecting tourists’ hands?
There are six species of commonly occurring British gulls and the ones you are most likely to encounter at the beach are herring gulls, lesser black-backed gulls, and great black-backed gulls. They have a varied diet which includes fish and marine invertebrates, as well as insects, rodents, offal, carrion, fruit, seeds, eggs, reptiles, amphibians, and other small birds.
However, loss of habitat has forced gulls inland where they have adapted their diet to include human waste particularly from landfills and in urban areas. And it appears, that gulls, just like humans, have become addicted to ‘junk food’ favouring it over natural sources of food.
To show this, in 2020, a team of scientists from the University of Bristol found that gulls living in a city timed their foraging to maximise the food they could acquire from human activity.
The researchers fitted mini GPS trackers to 12 lesser black-backed gulls and monitored their behaviour at three different settings; a public park, a school, and a waste centre all not far from an abundance of marine food in the Severn estuary.
They found that although in the park the gulls’ feeding activity corresponded with the availability of natural food sources, at the school they foraged more during break times and didn’t visit at the weekends. Similarly, at the waste centre which received up to 15 loads of waste a day during the week, the gulls foraged more during the opening and closing times and didn’t turn up at the weekends.
To understand why gulls have gone from simply foraging for human food, we need to look at their behaviour in the wild.
Although they usually hunt for their own food, gulls are opportunistic kleptoparasites, that is they sometimes feed by deliberately taking food from another animal. Other coastal species such as skuas also feed in this way usually by chasing other seabirds, and even blackbirds sometimes engage in kleptoparasitism, stealing snails from other thrushes.
While kleptoparasitism can take time and energy that could otherwise be spent searching for food, the benefits often outweigh the costs, especially when food is scarce. A study by Middlesex University looked at how a coastal population of gulls foraged on a beach in Norfolk compared to an urban population at Billingsgate Market in London.
Over the course of a year, the study found that kleptoparasitism was higher at Billingsgate, with population density, prey size, and site being the best predictors of this way of feeding. The researchers concluded that the large population of gulls and large food items providing visual cues at Billingsgate meant that kleptoparasitism was a more effective strategy than foraging for food directly.
In 2023, researchers from the University of Sussex found that gulls stealing chips is actually a sign of intelligence. The birds appear to learn from humans by copying their food choices, a behaviour known as stimulus enhancement or social learning.
To test this, the team placed one blue and one green crisp packet near individual herring gulls and groups of gulls along Brighton’s seafront. Nearby, a human experimenter ate from either a blue or green packet. The gulls were seen watching the person closely and, in most cases, pecked at the packet that matched the colour the person was eating from, suggesting they associated the colour with food.
The findings support the idea that gulls haven’t naturally evolved a taste for chips, but instead have adapted to human environments by learning to interact with people as a way to find food.
It seems there might be a surprisingly simple solution to prevent gulls from stealing your chips, ice creams, and sandwiches – just stare at them!
Researchers from the University of Exeter placed a bag of chips on the ground and measured how long it took for a herring gull to approach the food when a human was watching them compared to when the human was looking away. They tried the experiment with 74 gulls, but most flew away or refused to approach, with only 19 gulls completing the test. This suggests that only a small number of gulls engage in food-snatching.
For the 19 gulls that participated, they took an average of 21 seconds to approach the food when the human was staring at them. However, there was a lot of variation in behaviour. Some gulls approached quickly in both situations, while others were much slower when the human was looking at them.
This experiment shows that reducing conflicts between humans and gulls could be as simple as making small changes to human behaviour. However, we must also consider the different personalities of individual gulls. For example, some might be more confident after past experiences of being fed by humans or successful food-snatching attempts, making them bolder.
So, the next time you’re enjoying fish and chips at the beach, keep an eye out for approaching gulls – and try staring them down!
