Seagulls wearing GPS backpacks have revealed that the urban birds have fined-tuned their foraging schedules to human activity in cities.

In the study by the University of Bristol, tracker backpacks were fitted to 12 lesser black-backed gulls to record their behaviour.

The number of gulls at three different settings in the city – a public park, a school and a waste centre – was also observed.

Results showed the birds’ foraging patterns closely matched the timing of school breaks and the opening and closing times of the waste centre.

With this study in Bristol we have shown that gulls in cities are able to adapt their foraging schedule to make best use of food resources depending on their availability

Their activity in the public park appeared to correspond with the availability of natural food sources, such as insects and earthworms.

The findings, published in Ibis, the International Journal of Avian Science, suggest gulls have the behavioural flexibility to adapt their foraging behaviour to human time schedules.

This trait helps the birds to thrive in cities.

Dr Anouk Spelt, lead author, said: “Our first day at the school, the students were excited to tell us about the gulls visiting their school at lunchtime.

“Indeed, our data showed that gulls were not only present in high numbers during lunchtime to feed on leftovers, but also just before the start of the school and during the first break when students had their snack.

“Similarly, at the waste centre the gulls were present in higher numbers on weekdays when the centre was open and trucks were unloading food waste.

“Although everybody has experienced or seen gulls stealing food from people in parks, our gulls mainly went to park first thing in the morning, and this may be because earthworms and insects are present in higher numbers during these early hours.”

Dr Shane Windsor, co-author of the study, added: “With this study in Bristol we have shown that gulls in cities are able to adapt their foraging schedule to make best use of food resources depending on their availability.

“Some gulls even used all three feeding grounds in the same day, suggesting they might track the availability to optimise their energy intake.

“These results highlight the behavioural flexibility of gulls and their ability to adapt to the artificial environments and time schedules of urban living.”