Seagulls are moving more into urban areas — risking an outbreak of bird flu

This won't surprise most people, but seagulls didn't evolve to eat your french fries. They typically eat what's around the ocean, whether it's fish, molluscs or small mammals. Nonetheless, human wastefulness and urban expansion are providing ample food sources for these birds, which is seeming to significantly change their behavior, specifically where they prefer to live. And it turns out, thanks to our interference, the "sea" in seagull is slowly losing its meaning.

In a recent study published by the journal Ecological Informatics, the researchers used AI modeling that relied on environmental data from specific locations to learn why short-billed gulls (Larus canus) in Fairbanks, Alaska had swapped habitats. Although short-billed gulls typically live along coastlines and other bodies of water, these gulls had moved to human-made structures like parking lots, garbage dumpsters and industrial gravel pads over a span of months.

They were specifically targeting the normal habitats of scavenging ravens, which they had studied before, but what they found was that the two species engaged in what amounted to a territory swap. Ravens take over in the winter and seagulls move in over the summer. When the scientists completed their analysis — which drew on U.S. census data and urban municipality data to paint as complete a picture as possible of the conditions surrounding the gulls' habitat swap — they concluded that, quite simply, human wastefulness was the primary culprit.

"We find that Short-billed Gulls prefer the synergy of industrial areas near man-made water bodies, impervious surfaces, gravel pits, strip malls, transfer sites (garbage dumps) and some young forest vegetation," the authors explain in their introduction.

This information has potentially serious real-world implications. In an interview with the publication Phys.org, University of Alaska Fairbanks professor Falk Huettmann — who served as first author on the paper — explained that these gulls are not innocuous visitors to the human scene. They carry with them the threat of infection outbreaks.

"Gulls are known as the leading vectors of diseases," Huettmann, who is also associated with the university's Institute of Arctic Biology, explained. "They suffer overwhelmingly from bird influenza. What we demonstrate in the maps are essentially disease reservoirs which happen to coincide with human development."

In the study itself, the authors argued that their research methods — which drew heavily from the research of citizen scientists over three years throughout urban Alaska — could also be of broader value to the public.

"The creation and use of city- and gull-specific predictors should be encouraged and utilized to produce novel outputs, e.g., E. coli map, contaminants and disease transmission risk maps," the authors write. "Zoonotic diseases, and the role that gulls and cities play as reservoirs and spill-over areas for avian influenza should also be considered, as well as OneHealth approaches. From an urban planning perspective, analyses can be expanded to issues of contamination, power plant associated heavy metal loads, water quality, heat islands, and man-made climate change."

Indeed, the research itself was accumulated through methods that the authors refer to as a "Big Data approach." This means that they took advantage of open access data that already existed for habitat and urban analysis, in addition to data from field sources and the aforementioned federal and citizen scientist information. The authors argue that their study is the "first-known attempt" to blend the Big Data approach with alternative model assessments to learn more about the behaviors of urban seabirds.

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If the roaming gulls pose a threat to human health, it is not like humans are in a position to complain of unfairness; if anything, the recent history of human-bird relations has for the most part entailed people wronging their feathered friends. Climate change, for example, is killing Atlantic puffins and other seabirds that are unable to adapt to these changes. Because climate change transforms the ocean currents like the Labrador Current, the warm Gulf Stream is expanding and prompting many North Atlantic fish species to leave their traditional habitats. Their new homes are colder water that is too deep or too far away for seabirds to reach in order to feed their young. Puffin chicks similarly suffer from the erratic weather, with intensified storms drowning their nests and taken a deadly toll on seabirds in numerous other ways.

Similarly a 2023 study in the Journal of Hazardous Materials found that flesh-footed shearwaters are suffering from a disease called fibrosis as they accumulate scar tissue from eating too much plastic pollution. Plastic pollution is directly linked to climate change as most synthetic polymers today are made from fossil fuels. Because these plastics never biodegrade, they remain in our ecosystem forever, often inflicting damage on the hapless wildlife that encounters them.

"While these birds can look healthy on the outside, they're not doing well on the inside," Dr. Alex Bond, who co-authored the study and is principal curator of birds at the Natural History Museum in London, said in a statement at the time. "This study is the first time that stomach tissue has been investigated in this way and shows that plastic consumption can cause serious damage to these birds' digestive system."

The relationship between humans and seabirds is a complicated one. For every child who is delighted by seabirds as they congregate on a beach or act like "sea rats" in famous movies like "Finding Nemo," there are humans who risk getting sick from interacting with these disease vectors — and there are countless birds suffering in real ways from human activity like climate change and plastic pollution.

Clearly more research needs to be done so humans can learn about exactly how they attract these seabirds into our urban spaces, as well as how we can make sure our industrial activity does not interfere with their lives in the natural world.