Herring gulls have wrecked many a seaside picnic, pouncing on unsuspecting people trying to enjoy a Cornish pasty, a sandwich or a bag of chips.

But a study from the University of Exeter suggests gull chicks prefer seafood even after being raised on a diet of the sort of scraps found around humans.

Scientists studied herring gull chicks that had been rescued after tumbling out of nests in roofs in towns across Cornwall. While they were in captivity, they were given either a “marine” diet consisting of mainly mackerel, sprats and mussels, or an “urban” diet, mostly bread and cat food.

Every few days the chicks were presented with a choice of four foods in different bowls, to test which they preferred – and all of them strongly favoured fish. “When fish is available they clearly prefer it,’ said the lead author, Emma Inzani, from the Centre for Ecology and Conservation at the University of Exeter’s Penryn campus in Cornwall.