Seagulls living in the city prefer food that has been touched by humans: an experiment conducted on the street by British researchers from the University of Exeter proves it. The results, published in the Royal Society Open Science journal, suggest that the bad management of municipal waste could strengthen this habit of feather grass, increasing its presence in urban areas and upsetting their feeding.
"Although seagulls are common in many cities, we still know little about their behavior in the urban environment," explains study coordinator Madeleine Goumas. "We therefore thought to investigate whether they are simply attracted to the sight of food or whether people's actions can somehow draw their attention to specific objects." To find out, the researcher approached individual seagulls encountered on the street in two cities of Cornwall and placed two buckets in front of them that hid wrapped sweets. After removing the containers, he held one of the two sweets in his hand for 20 seconds and then threw it back on the ground next to the other, and then left. Of the 38 seagulls tested, 24 caught one of the two sweets and 19 of them (79%) chose the one that had been held in the hand.
The experiment was repeated using sponges instead of sweets, but in this case the seagulls pecked the two objects with the same probability, showing to observe human behavior only when there is food at stake.
The birds at the center of the study are herring gulls, 'relatives' of the herring gulls of the Mediterranean "which now also nest in Rome and Venice", explains Andrea Galimberti, zoologist of the University of Milan-Bicocca. "Their presence has increased in the last 20 years because in the city they find an inexhaustible source of food, the absence of competitors and the protection from predators guaranteed by the presence of man. They are intelligent birds able to learn new foraging techniques and then pass them on from one generation to the next: to discourage their presence, it is crucial to educate citizens not to leave food remains on the ground and above all to improve the management of municipal waste, so that they do not stay on the street for days and days ".