The experiment was all about crisps. Feist and her colleagues presented crisps in either blue or green packets to groups of herring gulls, and then sat down about 5 metres away. The observer then either just sat and watched, or pulled a packet of crisps out of their bag and started to eat them.
When the experimenter was eating crisps, the gulls approached the packets 49 percent of the time, compared to 19% when the observer was just sitting around. But when the observer was eating crisps(and this is the clincher for me), the birds pecked the packet which was the same colour as the one that the observer was eating from 95 percent of the time.So, this appears to indicate that a) the food choices of this group of herring gulls can be influenced by what humans are eating and b) that it isn’t in this case just about the type of food, but that they even take the colour of the packaging into account, to make sure that they are eating ‘our’ food. I find this astonishing, and you can read the whole article here.
This increasing attunement to the way humans behave is probably coupled with the way that herring gulls have changed their habits, from being largely coastal to coming inland and feeding from landfill sites. They nest on flat roofs everywhere, and are often seen to be a menace, in spite of the fact that they are declining and are on the IUCNs Red List of endangered birds in the UK. We are fast becoming their main source of food, so no wonder they are paying more attention to the finest nuances of our behaviour. The effect of all that junk food on the gulls themselves would be interesting to monitor.
Incidentally, a 2019 study showed that gulls are much less likely to steal your chips if they think you are watching them – only 26 percent of a sample of gulls touched the food if they were being stared at, and they took 20 percent longer to approach than if the experimenter was busy doing something else. So if you don’t want to be ambushed and chipless, it pays to be diligent, as it does in most situations. I wonder if the rise of the smartphone could be correlated with the increased success of herring gulls stealing food? Now that would be an interesting study.
And here is one of my favourite short films, of a herring gull ‘puddling’ for worms and then announcing their presence with a most gratifying ‘long call’. Just look at that intelligent expression! These are extraordinary birds, well worth our attention.