Seagulls favour food that has been handled by humans, new research shows.
When herring gulls in British seaside towns were presented with two identical food items, one of which they had seen a human holding, they pecked at that one more often, suggesting they are influenced by human actions.
The University of Exeter study follows previous research which found that staring at seagulls makes them less likely to steal food.
“UK herring gull numbers are declining, but urban populations have increased,” says Madeleine Goumas, the lead researcher for both studies.
“Despite the fact they’re a common sight in many towns, little is known about urban gull behaviour. We wanted to find out if gulls are simply attracted by the sight of food, or if people’s actions can draw gulls’ attention towards an item.”
The study was small and relatively simple, but the results were pretty clear-cut.
In Cornish towns such as Falmouth and Penzance, researchers approached individual gulls and placed two buckets on the ground in front of them, each covering a wrapped flapjack.
The buckets were then removed, and the researcher picked up one of the flapjacks, handled it for 20 seconds, then put it back down on the ground.
Of the 24 gulls who came forward to peck at a flapjack, 19 (79%) chose the one that had been handled.
To see if gulls were responding to human handling alone, the experiment was repeated with sponges that were cut into the same size and shape as the flapjacks. In this case, the gulls’ preference for the handled sponge did not exceed “chance levels”.
“Our study shows that cues from humans may play an important part in the way gulls find food and could partly explain why gulls have been successful in colonising urban areas,” Goumas says.
It also means gulls are moving away from their natural diet of fish and invertebrates, adds colleague Laura Kelley, and the effect of this change is not yet clear.
The study is reported in the journal Royal Society Open Science.