Humans impact animal behavior in many ways, but can our food choices impact what other animals decide what to eat? A study from researchers in England seems to suggest we can. Franziska Feist’s team studied gulls on a popular beach, trying to investigate how human behavior impacts gull food choice. Today, many types of animals live in environments with heavy human presence. Gulls, for instance, are frequent visitors to beaches, piers, and urban settings near bodies of water that have a lot of traffic from humans. So adapting behavior to coexist with humans most likely leads to higher foraging success.
Living in urban environments, as many gulls do, requires flexibility in foraging—the food someone dropped one day may not be there the next day. Having that kind of flexibility demonstrates advanced cognitive abilities in the birds. Gulls also are food-stealing birds and previous studies have demonstrated that animals who steal food have strong abilities to combine information about others—both of the same species and of different species—with information about their environment in order to decide when they should steal, what food to steal, and who they can steal from. While it may seem like gulls simply eat leftover street food, there is actually a lot of high level cognition occurring behind food choice decisions. Foraging is also a very social behavior for gulls—often, they will go towards a food source after watching other gulls flock at that site. All together, these observations led the researchers to question whether human behavior could influence gull choice.
Feist’s team had two food options laid before wild gulls: chips in a blue package and chips in a green package. Researchers tested two different conditions: one with a human present, but not eating and one with a human eating either the blue packaged chips or the green packaged chips. Then, the researchers watched to see how the gulls would respond. Behaviors like head turns, approaches towards the packages, or pecks at chips that indicate interest were video recorded. They discovered that all three behaviors (head turns, approaches, and pecks) increased when a human was eating compared to when a human was not eating. The very sight of a human eating similar food to what was available for the gulls to eat was very intriguing to the birds. The researchers wondered if bird age had any factor in this interest—maybe the older birds with more experience learned to give more attention to food humans were eating. While the number of head turns and approaches did not differ by age, there was a significant difference in how adult and juvenile gulls pecked at the foods when a human was also eating. Even though fewer than half the birds were adults, they made up 86% of pecks, suggesting that learning throughout a gull’s lifetime helps them better adjust to living in environments with humans. When it came time to actually eat, the gulls chose to eat the same package of chips as the human 95.45% of the time. The results suggest that not only were the birds intrigued by the human behavior, but also that the gulls based their own food choice on that of the human.
Gull reaction to cues from humans to make their own food choices illustrates a high level of cognition in the gulls. Such attention towards human behavior is common in domesticated animals like dogs—think of a dog finding hidden food by following a finger pointing—but less common in animals that are not domesticated. The gulls’ ability to adapt to and read human behavior suggests that living closely with humans leads to adaptation to human behavior. However, similar behavior has been seen in other food-stealing seabirds that do not live in close contact to humans, making it difficult to prove definitively that living in close contact leads to adaptations that allow birds to react to human behavior. Regardless, the findings indicate that our behavior can make foods more attractive to gulls.
Feist, F., Smith, K., & Graham, P. (2023). “Inter-species stimulus enhancement: herring gulls (Larus argentatus) mimic human food choice during foraging.” Biology Letters, 19(5), 20230035. https://royalsocietypublishing.org/doi/10.1098/rsbl.2023.0035
