Researchers from the Memorial University of Newfoundland and Labrador in St John’s examined 133 adult ring-billed gulls living in four locations and tested their blood for omega-3 fatty acids to find out how much human food they had the compared with a natural fish diet. They then put the gulls through an intelligence test called the “string-pull test”. It is a test which is frequently used by animal behaviourists to work out how good at problem solving a particular animal is.
Jessika Lamarre, the lead author, of the study said:
“There was a clear distinction between those eating mostly marine food having little success at solving a test and those relying on human food having much better success.”
She said that their proficiency was on a sliding scale by which he meant that the more human food a seagull consumed in their diet the better they were at solving intelligence test problems.
The conclusion is that the challenges of stealing food from people improves intelligence. It is not that the food improves the brain but the challenges encountered when seagulls grab food from tourists at the seaside that improves their brain function.
“We think that gulls exploiting anthropogenic food were better at problem-solving because they might have more experience manipulating human objects to obtain food. They likely also employ a larger range of foraging strategies than gulls exploiting the marine environment, so they might be able to come up with problem solving strategies quicker.”
As I said, Lamarre, is stating in a roundabout way that when gulls have to forage by ‘stealing’ food from people under what must be challenging and even hostile conditions, they have to have to have their wits about them to a higher standard than they would if they were flying behind a trawler picking up dead fish floating on the surface of the sea.
A 2019 study from Exeter University found that when a human holding a bag of chips stared at a gull who wanted to eat one of those chips, the gull was reluctant to approach and on average delayed doing so for 21 seconds.
The study is published online: Science of the Total Environment.