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This article is part of Birdopolis, a three-part series that explores the lives of birds that are, by accident or design, spending more time in urban environments. The others are “Honolulu: A Seabird’s Surprising Five-Star Destination” and “The City, the Sparrow, and the Tempestuous Sea”.
Watch the recording of our webinar “Birdopolis: Coastal Birds at Home in the City” for more on the urban lives of gulls.
The house didn’t beg for attention. A modest home, with a modest garden, on a nondescript street. Pigeons gathered on the terrace above, a congregation that would hardly draw a glance from most passersby. But its presence here—and only here—offered subtle confirmation that Anouk Spelt and Cara Williamson were in the right place. “X marks the spot,” the birds seemed to call.
Intel agreed. The researchers were chasing something, and GPS data confirmed their quarry visited this place with uncanny regularity. Armed with clues on a hunt for answers, they took the final steps and knocked on a stranger’s door.
Looking back on their experience that day in Bristol, England, four years ago, the researchers can’t help but laugh. There’s really no graceful way to ask someone what they do every day, and the homeowner was understandably suspicious of unexpected guests asking probing questions. When we asked what happened every day at 6:00 p.m., he did not want to tell us at first, recalls Spelt.
His expression softened, however, when Williamson drew a small plush bird from her bag and pointed out its tiny backpack—a teaching tool used to explain how GPS trackers are attached to birds—and described the flight path recorded by one such tracker. One of the gulls in their study group touched down in this garden with clock-like precision. Understanding the reason why would help unravel a mystery.
Gulls spend much of their lives looking us over, but they’re easy for us to overlook. They seem so ubiquitous, so ever-present that they’re just, well, “around” and part of the backdrop. Except, of course, when they crap on our car or our coat, or swoop in on a French fry. A propensity for such behaviors has earned gulls a reputation as common pests, and along with it, nicknames like dump ducks, shit hawks, and beach chickens.
It’s an animal almost everyone can identify, at least in a general sense—gull—but people sometimes forget that they’re wild birds with wild roots. There are in fact around 50 species, ranging from the dainty little gull, not much heavier than a large lemon, to the great black-backed gull, a bruiser by comparison whose wingspan is about as wide as most women are tall.
The fact that some gulls spend time inland, away from the coast, makes the term seagull a misnomer, but it’s not hard to see where this widely used moniker got its wings. Gulls are, and have always been, true emblems of the ocean. Along with terns, noddies, and skimmers, they’re grouped in the family Laridae, species that are, for the most part, seabirds.
It’s no surprise then that the birds appear in the art and stories of coastal Indigenous communities, including the Inuit, Innu of Labrador, and Nuu-chah-nulth from Canada’s west coast. And in his 2018 book, Landfill, British birder Tim Dee describes gulls of the not-so-distant past as “keeping cold company with oceans, storms, and ice.” Gulls, he says, “long remained tokens of the far-from-home and the storm-tossed.”
If the soundtrack to your lunch is the consistent ke-yah, ke-yah of the hungry seabirds, it’s hard to imagine such a time described by Dee: when gulls’ lives weren’t so intertwined with our own. Today, these gregarious, bold birds can seem like they’re everywhere. But surprisingly, we began sharing our cities with them only recently. Not that long ago, gulls were the occasional tourist, not that guest that overstays its welcome.
The story of that shift is not a Hitchcockian rise of the “sky rats,” but a testament to gulls’ adaptability to a changing world—one rife with warnings about our impact.
Urbanized gulls were once unheard of in Bristol, where Spelt and Williamson have been tracking gulls with the University of Bristol’s urban gull project. As an aerospace engineer, Williamson has always been fascinated with things that fly. But it wasn’t until she began designing drones that her interest in birds took off. Together with Spelt, a marine biologist, she hopes that studying the flight patterns of city-dwelling gulls will help us understand not only how the birds navigate complex cityscapes, but also why they stick around and how we might get along in the changing world.
The United Kingdom’s Clean Air Act of 1956—which prevented the burning of garbage—played a major role in the birds’ urban arrival. All of a sudden, waste was amply available in open landfills, and plucking up easy meals bolstered existing populations.
That pattern continued throughout the nation following the end of rationing and a post-war boom in spending. People were buying more, and existing landfills were no longer suitable for the amount of food waste being produced. As new sites sprang up to contain the leftovers, gulls continued to follow the garbage.
By 1970, around 1,300 pairs of herring gulls and lesser black-backed gulls were recorded nesting on British Isle rooftops. In 1994, that number had grown to at least 13,000, and by 2004 it had topped 100,000.
It’s a trend that’s echoed in many cities around the world, and with it has come a general resentment toward these avian neighbors. There’s a reason a collection of gulls is sometimes referred to as a squabble. The birds can certainly be noisy. Support of gull culls has gained favor with many people—up to 50 percent among some demographics—bolstered by reports of thievery, noisy nights, poop-pummeled property, and mobbing behavior.
This is a familiar story with a predictable final act: humans create an abundance of food, wildlife comes to the table, and some of us inevitably decide it would be better if those animals were repossessed by the wild from whence they came. The trouble is, portions of their wild habitats may no longer support them like they once did.
On the other side of the world from Bristol, Louise Blight, a seabird ecologist at the University of Victoria in British Columbia, also studies gulls and their move to become urbanites. She has been observing glaucous-winged gulls—one of many species in the genus Larus, the large, white-headed birds most people imagine when they hear the word gull—near the city of Victoria since 2008.
But she’s not studying these seabirds because they’re taking over; she’s looking for gulls in the city, in part, because they’re missing somewhere else.
The adaptable birds, like many others, build their nests with a range of available vegetation. In the spring of 2009, on one of Blight’s study sites—the Chain Islets and Great Chain Island about two kilometers from Victoria—they added sedum, a green succulent. Woven with the plant’s pink and yellow flowers, over 1,000 carefully crafted “wreaths” announced themselves against the monochrome backdrop of rock.
The gull colony is a rewarding place to spend time, Blight says. “It’s crowded and busy, so everybody is coming and going and doing whatever it is that they’re doing at that part of the nesting season. Pairing up with their mate, or building a nest, or sitting on eggs, or bringing food to their chicks. It’s just a place that’s full of life.”
Each nesting pair will return to these colonies to breed for the rest of their lives, which, if they’re lucky, will be more than 30 years. But many offshore colonies are shrinking.
Glaucous-winged gulls are in decline in parts of their range, and have been for decades. The population in the Salish Sea—a network of coastal waterways that includes the Chain Islets—has been more than cut in half since 1986. In the mid-1980s, an estimated 13,000 pairs of glaucous-winged gulls were thought to be breeding in the region. The most recent survey, which took place between 2009 and 2010, pegs that number at around 5,600.
As in Bristol, some gulls in the Salish Sea have chosen to settle in Victoria and other nearby cities in recent years. Blight wondered if studying these urban gulls might offer clues about what was contributing to the decline offshore. In 2017 and 2018, she spied on roof-nesters in Victoria, and its surroundings, via drone. But the surveys led to more questions. The study turned up about 350 rooftop nests, representing far fewer breeding pairs than have disappeared offshore. Even though some gulls have chosen to nest among us, it isn’t as if the missing gulls just relocated to the city, explains Blight, despite what a stroll through the city might lead you to believe.
“I would have thought there were far more gulls than we found using the drones,” she says. “They’re so noisy and so present. They hang out on the edges of buildings, looking down and shrieking, so they seem more numerous than they are.”
For this reason, the notion that gulls are in any kind of trouble is a tough pill to swallow for humans living in close quarters with them. It seems impossible that there could be anything other than more of the boisterous birds than ever before. The reality is that similar declines are documented in many gull species.
The ivory gull, a high-Arctic bird whose stark plumage mirrors the sea-ice habitat it depends on, has declined by 70 percent in parts of its range over the past 40 years. New Zealand’s native red-billed gull—known for its habit of pilfering picnics—is in the midst of a serious slump. In the United States, some gull colonies have all but disappeared. Washington State’s Colville Island, for example, hosted about 1,800 pairs of glaucous-winged gulls in the 1970s. In 2000, only around 20 pairs remained. Even the species allegedly “plaguing” British cities, such as lesser black-backed gulls, are in decline overall.
It’s not time to sound the alarm for glaucous-winged gulls just yet. They’ve been in decline in the Salish Sea for over 20 years, but they are still numerous, explains Blight. However, looking at gull numbers from a bird’s-eye view tells a cautionary tale about the health of our oceans and the state of urban landscapes.
“Even though they have this reputation for stealing people’s pizza and French fries, they’re still marine birds, and they still need fish to do well,” she says.
Gulls gobble down a wide variety of prey—from crabs and other invertebrates, to seeds and fruit, to the chicks of other gulls—but forage fish such as herring remain a staple menu item. The gulls that are nesting on rooftops in Victoria still bring fish to their chicks, says Blight. “Fish are really high-fat food, and chicks need them to grow quickly and fledge strongly.”
Fish and other marine prey are undoubtedly better for gulls than scraps of human food, but interestingly, gulls that opt to nest on rooftops appear to be moving farther inland. The 1986 survey in Victoria found that gulls were staying within 500 meters of salt water. But some 30 years later, Blight’s team found gulls as far as the outer edge of their survey area, which stretched 970 meters from shore.
Spelt and Williamson managed to place trackers—tiny devices that are worn like backpacks and do not disturb flight—on 11 lesser black-backed gulls nesting on Bristol rooftops. And as in Victoria, some of Bristol’s gulls are also spending longer stints farther from the sea.
Although the reasons are likely multifaceted, Spelt and Williamson suspect there might be a pattern emerging—one that comes down to predictability. You can go to the sea and maybe get a higher-nutrient fish, but if it costs you more energy to find it, explains Spelt, it might not be worth the journey.
Today, gulls around the globe have to work harder for their traditional food.
Unlike penguins, gannets, and other seabirds, gulls can’t dive very deep. Instead, they hunt in areas where piscine fare hangs out near the surface—and their favorite foods are also coveted by the fishing industry. This overlap may initially have given rural gull populations a helping hand. By following vessels in search of scraps, gulls didn’t have to spend as much energy hunting. But modern regulations around fishing discard have greatly reduced that opportunistic food source.
In the Salish Sea, herring and other forage fish have been less available to gulls. “They have also been documented to be smaller in size at a given age, at least in some years, and their spawning period is also decreasing,” notes Blight. “It used to be that there was this temporal spread of availability of different fish because they spawn at different times. And as some of those fish species have dwindled, there’s a contracting window of when seabirds and other foragers can access that food.”
Declines in nesting success—both egg size and clutch size—have been attributed to reductions in forage fish in other gull species. But in some places, scraps seem to be filling the dietary gap.
Bristol’s urban gulls, for instance, largely abandon ocean foraging when the time comes to reproduce. Only five of over 21,000 GPS locations collected from Bristol’s roof-nesting gulls were marine foraging sites. And all five belonged to a single bird.
“I thought they would go to the sea more than we saw,” says Spelt of the gulls in her study. “That was really interesting.” But roof-nesting gulls don’t just fly around aimlessly until they spot a trash tumbleweed or lone French fry. Each bird makes its own designated stops, perfectly timed with the hustle and bustle of human activity. This is possible thanks to gulls’ incredible memories and intelligence. “These birds are so smart … that they completely adapt to our lives and what we do,” says Spelt.
Back on that stoop in England, Williamson and Spelt got the answer they were looking for. What happens every day at 6:00, in that unassuming garden, is the delivery of calories.
Every night after eating, the family throws dinner scraps into their garden for birds and other wildlife. And, like clockwork, one gull in the researchers’ study group comes to collect the day’s offerings.
Other gulls in the study were equally timely in their arrival at feeding sites. Some birds regularly flocked to schools during lunch breaks, when children are most likely to drop food or leave sandwiches unattended. Then, it was off to the dump, to meet trucks when they tip the day’s haul.
Similarly, when farmers in agricultural areas tilled their fields, gulls met them there, ready to follow behind tractors for a tasting menu of worms, insects, mice, or frogs that were shoogled to the surface. Some gulls frequented sports fields during game season, where round-the-clock lighting meant food could be easily spotted after dark.
“A lot of people don’t realize that these birds are making daily commutes,” says Williamson. “We tend to think of [commutes] as a very human thing, but these gulls are going to their favorite places, day after day. They even vary their route depending on the conditions, like we do with traffic.”
Foraging grounds with the most food tend to also have the most competition, and anecdotal evidence suggests gulls will adjust course if they’ve come to the table too late. What’s more, the path they take to each feeding ground changes with the weather. Urban sprawl creates complex wind flows, which can present control issues for small drones. Williamson and her colleagues analyzed the tracking data to look at how gulls, on the other hand, use those flows to their advantage.
During 193 commutes, she found that gulls made fine adjustments to their gliding and flap-powered flight speeds, based on feedback from their innate wind-sensory abilities. By making use of shifting thermals and updrafts from buildings, the gulls saved as much as 30 percent of the energy required to fly. Thermals over landfills and industrial areas also offer energy savings for gulls. Instead of being tossed around like unwieldy drones, the birds use a city’s wonky weather to facilitate additional soaring opportunities.
Impressive commutes have also been documented elsewhere. A lesser black-backed gull in the Netherlands, for example, was tracked flying 97 kilometers and back in a single day. “It flew from the island Texel to Amsterdam to visit a specific chip shop,” says Spelt.
Once gulls move into a city, they’re difficult to dislodge. And it’s their cleverness and adaptability that makes it such a challenge. Staying in the city offers birds more of a leg up than just a consistent menu and energy savings during flight. Roof-nesting gulls have built-in protection from foxes and other predators, and warmer temperatures above city sidewalks mean the birds can lay eggs earlier in the season. If the first attempt fails, there’s still time to lay again.
Not everyone is so enamored with the gulls’ craftiness, however. The breeding season sees the biggest influx of gull-human conflict. And gull deterrents like pyrotechnics and gull-spooking raptors can run cities thousands of dollars per day. The trouble is, very few gull deterrents have proven effective long term, and some have lasting effects on the birds.
Egg oiling—a process that involves coating fertile eggs to stop the flow of oxygen, before returning them to the nest—kills chicks before they hatch. But with parent birds none the wiser, they still devote an immense amount of energy to incubating their duds. Similarly, gulls tend to rebuild their nests in harder-to-reach places if they’re removed.
Bird netting, which is hung around popular nesting sites, is particularly nefarious for gulls. While the mesh is intended to stop adults from returning, they can instead be trapped by their wings until they die.
Williamson believes that looking at our own behavior will offer more effective solutions than trying to stop gulls from doing what they do best: adapting. “If people want to solve the gull ‘problem,’ they have to solve the waste problem,” she says. “We invited them in with open arms, and now we’re saying, ‘You can go now, we don’t like you anymore.’”
Covering garbage and not actively feeding gulls are good places to start. And while stories of human-stalking gulls tend to make a splash in the news, the chances of being attacked by a gull are actually quite slim. A gull is far more likely to scream at, vomit on, or poop on you—in that order—than actually swoop. Most conflict near human homes arises because a chick has fallen from its nest, which sends the parent bird into protective mode. Wearing a hat, or using an umbrella, usually takes care of a threat in that situation. New research suggests that making eye contact with certain gull species can also lessen the likelihood they’ll go for your lunch.
Gulls might be bugging us, but Blight explains that’s in part because they’re great parents. “That’s partly why they are swooping down, shrieking from rooftops. They’re defending their territory and they’re defending their chicks,” she says. “I remember I was traveling back home on the ferry one day, and I saw a toddler running up toward its parent and hanging on [their] leg and I thought, Oh, that reminds me of the gulls.”
Blight, who has spent many years working on and alongside the ocean, hopes appreciation for these consummate users of the wind won’t be lost in the conflict. “It’s always impressive when you’re out there at sea, having a hard time in bad weather, and these … birds are just soaring along on the wind that’s causing you so much trouble,” she says.
The next time you see a gull, take a moment to think about where it came from, and where it may be headed. Perhaps your paths have crossed along a daily commute: a chance meeting somewhere along a kilometers-long journey for a bite of fish and chips.