A team of researchers from the University of Exeter, UK, put a bag of chips on the ground and tested how long it took herring gulls (Larus argentatus) to approach when a human was watching them, compared to when the human looked away: on average, gulls took 21 seconds longer to approach the food with a human staring at them.
“Gulls in urban areas are often considered a nuisance owing to behaviors such as food-snatching,” said lead author Dr. Madeleine Goumas and colleagues.
“Whether urban gull feeding behavior is influenced by human behavioral cues, such as gaze direction, remains unknown.”
In the study, the scientists measured the approach times of herring gulls to a food source placed in close proximity to an experimenter who either looked directly at the gull or looked away.
“We attempted to test 74 herring gulls. Only 27 of these (36%) initiated the start of at least one trial. The remaining gulls either flew away soon after presentation of the food or did not approach on the ground within 300 seconds,” they said.
“Twenty-three (49%) of the 47 gulls that did not approach during a trial approached the food outside the trial conditions. Nineteen gulls (26% of all those targeted) completed the paired trials.”
Gulls took significantly longer to approach the food source when the experimenter looked at them versus away. The average difference in approach time between treatments was 21 seconds.
“Gulls are often seen as aggressive and willing to take food from humans, so it was interesting to find that most wouldn’t even come near during our tests,” Dr. Goumas said.
“Of those that did approach, most took longer when they were being watched. Some wouldn’t even touch the food at all, although others didn’t seem to notice that a human was staring at them.”
“We didn’t examine why individual gulls were so different — it might be because of differences in ‘personality’ and some might have had positive experiences of being fed by humans in the past — but it seems that a couple of very bold gulls might ruin the reputation of the rest.”
“Gulls learn really quickly, so if they manage to get food from humans once, they might look for more,” added Dr. Neeltje Boogert, senior author of the study.
“Our study took place in coastal towns in Cornwall, UK, and especially now, during the summer holidays and beach barbecues, we are seeing more gulls looking for an easy meal.”
“We therefore advise people to look around themselves and watch out for gulls approaching, as they often appear to take food from behind, catching people by surprise.”
“It seems that just watching the gulls will reduce the chance of them snatching your food.”
The study was published in the journal Biology Letters.
Madeleine Goumas et al. 2019. Herring gulls respond to human gaze direction. Biol. Lett 15 (8); doi: 10.1098/rsbl.2019.0405