Hakai Magazine

The living is easy, too easy, for raccoons living on islands with no predators. Photo by Shanna Baker
The living is easy, too easy, for raccoons living on islands with no predators. Photo by Shanna Baker

Bandits on the Beach

What island raccoons tell us about fear.

Authored by

by Jude Isabella

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The young scientist gripping the wheel of a motorboat slicing through the ocean waves has the last name Suraci—Icarus spelled backward.

It’s another scientist onboard who points this out. Michael Clinchy, a behavioral ecologist at the University of Victoria in British Columbia, is amused by the fact. His PhD student, Justin Suraci, smiles. Clinchy and Suraci study the ecology of fear. Raising the specter of the mythological Icarus (who, at his peril, ignored a warning to fly too close to the Sun), suggests there’s a certain hubris, a certain fearlessness in their study.

A chill, flung from the waves as the boat buzzes along, tinges the cloudless summer day. But it is June and warm in a survival suit. Field technician, Natalie Gray, inches down her suit’s zipper as she sits on the boat’s edge, gripping a line for balance. We’re headed to Penelakut Island, some 40 kilometers southwest of Vancouver, British Columbia.

Penelakut is one of the Gulf Islands strung between mainland Canada and Vancouver Island and surrounded by the Salish Sea, shaped by glaciers thousands of years ago. About eight square kilometers in size, the island is close to the protected Gulf Islands National Park Reserve and, like some of its island neighbors, Penelakut has an adult raccoon population with no predators—no cougars, wolves, or bears—and very little to fear in general. This is exciting for Clinchy and Suraci.

Illustration by Mark Garrison

Fear, at first glance, is straightforward: a predator wants to eat and that’s scary to potential prey, so they act to avoid becoming another animal’s lunch. But that’s only one strand in a complex web of events that unfold when fear is, or isn’t, present. Fear has benefits and costs—to individuals and to ecosystems.

When scientists study fear they tease out the consequences of an animal acting insecure versus secure, paranoid versus pronoid, vigilant versus relaxed. Then they look at how those behaviors ripple out beyond the individual. The research on fear in animals has broad implications for wildlife management. Knowing more about the role fear plays in an ecosystem will help manage animals like raccoons, omnivorous middlemen in the food chain. Clinchy is trying to piece this all together.

As they near shore, Suraci, 30, and Gray, 24, launch into a well-rehearsed routine. The petite Gray, her blond hair swept up in a knot, big sunglasses shielding her eyes, pulls out the anchor nestled in the boat’s bow and chucks it overboard. Then the pair flips over an inflatable dinghy on the bow and slide it into the sea, the sun sparkling off the water in pinpoints of light. Suraci and Gray load the dinghy with their equipment then climb in and paddle to shore. After unloading, one returns for Clinchy and the rest of the gear.

Lamalchi Bay is on the western side of Penelakut Island, the reserve of the Penelakut Tribe. The First Nation is interested in establishing a shellfish industry and Clinchy and Suraci’s research will help them better understand their main competitors: raccoons.

Raccoons are cocker-spaniel-sized creatures native to the Americas. The English name raccoon is thought to come from the Algonquin word arakunem, perhaps mispronounced or shortened by early English settlers in the eastern United States. It means “he who scratches with his hands,” and watching a raccoon eat, the name suits. They dip their hand-like paws into the shallows, pull up clams, crabs, or other prey, and rub it, as if scratching or washing. Their natural habitat is the forest, usually close to water, an important environmental feature for two reasons: shorelines offer easy access to food, and wet paws enhance a raccoon’s sense of touch—and probably its foraging ability.

For raccoons, shorelines offer easy access to food, and wet paws enhance a raccoon’s sense of touch—and probably its foraging ability. Photo by Shanna Baker

Raccoons are mesopredators—animals in the middle of the food chain—an ecological niche they share with other medium-sized omnivores, such as skunks, badgers, and foxes. Raccoons are native to Vancouver Island and the larger Gulf Islands, but it’s thought that they were introduced to some of the smaller islands, including Penelakut.

Clinchy, 50, jams a hat onto his blond head. Tall, and a bit bearlike in form, he has the gift of gab. He keeps up a running patter, cracking jokes as he and Suraci discuss camera and raccoon trap placement. To monitor properly, it’s necessary to think like a raccoon and imagine how they use the shoreline.

“I don’t know about that camera angle,” Clinchy says, gesturing to a camouflaged wildlife cam secured to a tree. “It’s like you’re Bertolucci or something.” Suraci laughs and adjusts the angle until Clinchy approves.

Clinchy has been investigating fear in the wild for more than a decade. With his colleague and partner Liana Zanette, an ecologist at the University of Western Ontario, he began looking at the effect of fear on birds on nearby Portland Island, just over 30 kilometers south of Penelakut. They focused on how the fear of predators—not the predators themselves—suppressed the reproduction of song sparrows on Portland Island.

In one significant study, Zanette, Clinchy, and their colleagues filmed 225 song sparrow nests on the island to figure out the birds’ main predators. Then they studied two dozen nesting song sparrows to test the theory that fearful birds had fewer offspring.

Song sparrows are shrub nesters, so the scientists put electric fences around the nests to stop predators like raccoons from eating eggs or nestlings. They also protected nests from larger aerial predators, such as hawks, with nets the smaller sparrows could still access. Then they set up speakers around the forest. For one group of sparrows, they played the sounds of predatory raccoons, hawks, owls, and crows. For another, they broadcast noises of non-predators such as seals, geese, hummingbirds, and loons. The scared birds spent less time sitting on their eggs; they were skittish and flushed from the nest more readily. They also spent less time foraging: a bird watching for predators can’t search for food at the same time. And birds not foraging are birds not eating, and not eating takes its toll—the stressed songbirds had 40 percent fewer chicks than the birds that heard the calls of non-predators.

“We showed for the first time in any wildlife, in any bird or mammal, that the fear itself can actually cause the prey to have fewer offspring,” says Clinchy, striding across the beach, skirting rocks slippery with rockweed. The song sparrows made a trade-off: they reproduced less, but at least they stayed alive.

The Gulf Islands research is particularly relevant in light of an ongoing debate over the impacts of reintroduced apex predators into Yellowstone National Park. After scientists relocated 32 wolves from western Canada to Yellowstone in 1995 and 1996, ecologist Bill Ripple watched a real world experiment unfold: how would wolves impact the food web? As expected, the wolves preyed on the big herbivores. But Ripple and other scientists studying the event were more interested in how the prey—primarily elk—changed their behavior. The cascade of effects was illuminating.

With the reintroduction of wolves, fear was reintroduced as well. And while it’s tough to say definitively that elk were running scared, two things happened after the reintroduction that probably affected the growth of plants like willow, a favored elk food: direct predation meant there were fewer elk foraging on willow, and, as well, the surviving elk foraged less in areas they perceived to be high risk. Fear had become part of the landscape.

It’s difficult to tease apart changes in population density and behavior, Ripple says, since the two were happening at the same time. It’s likely that a combination gave shrubs the opportunity to grow, in turn benefitting the area’s biodiversity.

But critics suggested that the declining elk numbers in Yellowstone was caused by other factors. Perhaps fewer cutthroat trout, a staple food for grizzly bears, encouraged the bears to prey more on elk. Or, drought had reduced the quality of elk habitat. Ripple shrugs off the critiques, defending his team’s studies. “Now that scientists are looking more at fear effects in ecosystems, they’re finding quite a few examples [that show how] fear alone can have a stronger effect than the direct killing,” he says over the phone from his office at Oregon State University.

Ripple points out that after planes smashed into Manhattan’s World Trade Center in 2001, millions of people changed their travel behavior. “The magnitude of the change from fear alone can be much stronger than any mortality effects.”

The real world of human behavior is a messy place, however, with multiple actors, dynamic environments, and individual personalities. It’s no different for wildlife. By focusing on small coastal islands with discrete animal populations, Clinchy and Zanette can control the number of variables in their experiments.

Islands are natural laboratories for studying evolution and animal behavior. Charles Darwin, for example, learned much from the Galapagos and Alfred Russel Wallace learned much from the Pacific Islands. Following their leads, Clinchy and Zanette chose Portland, Penelakut, and neighboring islands to study fear in birds and small mammals.

“We’re not looking at mega herbivores, big huge, migratory elk and what have you,” Clinchy says. “It’s a slightly different system but the principles should be the same.”

Behavioral ecology marries two areas of study—social behavior and ecology—which both explore the idea that an animal’s behavior has evolutionary costs and benefits. It’s possible that scientists compounded the difficulty of studying each subject area by combining them.

David Westneat, a behavioral ecologist at the University of Kentucky, points out that Charles Darwin wrestled with the study of social behavior, particularly altruism, an idea he feared might negate his entire theory of evolution. Why did individuals sacrifice their own survival to ensure the well-being of others? It took about a century before scientists established a theoretical framework for understanding altruism. In 1963, William Hamilton proposed kin selection to explain why an individual might sacrifice itself for the group. A vervet monkey, for example, endangers its own survival by calling out alarms to others when a predator appears. Altruistic genes survive because they benefit close relatives who might pass on the altruistic behavior.

Over in the field of ecology, scientists realized that the fate of a population as a whole was linked to individual behaviors or traits. In the 1940s and 1950s, Westneat explains, evolutionary biologist and ornithologist David Lack proposed that birds only raise as many chicks as they can nourish. Lack showed that female birds settled for an intermediate clutch size with the actual number of eggs varying from year to year, depending on conditions.

“A core tenet of behavioral ecology is that ecological circumstances can influence the benefits of a behavior, benefits being directly related to reproductive success and survival,” Westneat says. “And, of course, there are costs for certain behaviors. So the idea emerged that animals seek an intermediate behavior, balancing costs and benefits.”

By the 1970s, a strong interest in the function of behavior, and behavior as an adaptation, led to the emergence of behavioral ecology as a formal discipline. Today behavioral ecologists “are all wrestling with difficult things to test,” Westneat says. The effect of fear is a prime example.

John W. Laundré, assistant director of the James San Jacinto Mountains Natural Reserve at the University of California, Riverside, studies fear and the connection between prey and predators. He thinks that animal species likely vary in how they acquire fearful behavior. “The lower down you go on the taxonomic level, the more hardwired fear probably is,” Laundré says. “But in vertebrates, there’s a lot more learning than we expect. A lot of fear comes from experience.” Like most mammals, raccoons learn to run scared, and they often learn fear at a young age, which makes sense. Even an apex predator like a wolf begins life as prey—a vulnerable pup.

Close calls have a lot to do with instilling fear. Studies have shown that “a predator is approximately 20 percent efficient in hunting prey, so 80 percent of the time prey is escaping,” Laundré says. “If animals see their siblings get killed, or if they are almost killed themselves, they quickly learn their landscape of fear.”

Without such an education, animals are in real danger when a predator arrives on the scene. Mike Dickison, an ornithologist and curator of natural history at Whanganui Regional Museum in New Zealand, says that that’s what happened to the dodos in Mauritius and giant moas in New Zealand, which both went extinct within 200 years of the arrival of humans. They lacked a previous education in wariness to ground-based predators.

A bird that is hunted by humans and “that gets away can learn fear—but they have to get away,” Dickison says. “If there’s enough time, evolution can select for the birds more scared of humans.” Neither the dodos nor the giant moas had that luxury before they were wiped out.

Fear, it turns out, can be a powerful evolutionary force. But untangling the effects of fear in an ecosystem is like navigating the Labyrinth, a maze built by Icarus’s father—the path can be confusing and hard to follow without a thread.

Suraci arrived at the University of Victoria in 2012, hoping to untangle some of the effects of fear. A transplanted Virginian, today he wears the universal uniform of young biologists: plaid shirt, t-shirt, jeans, gumboots.

Suraci is measuring red rock crab caught in one of the five traps set the day before just offshore of the bay. Raccoons on Penelakut Island prey on the crab and Suraci wants to see the effect recorded calls of an apex predator will have on the raccoons, and, in turn, their prey. “What I’m interested in,” he says, “is [the importance of] fear induced by apex predators for protecting the prey of raccoons.”

The Penelakut, research is an extension of a study Suraci began on Portland Island in 2012. On Portland, Suraci and his colleagues spent a summer with their eyes glued to binoculars and cameras trained on raccoons to find out if the ring-tailed bandits were relaxed and secure, or fearful and anxious. The scientists played recorded sounds—of predators (cougars, bears, and dogs) and non-predators (seals)—and observed the raccoons. Suraci’s subjects had the same nonchalant reaction to a cougar snarling as they did to a seal barking. They had no fear of a predator that would send other raccoons running.

Island raccoons only fretted about the sound of one natural predator: barking dogs. The ancient indigenous people of the coastal islands had canine companions, and dogs never fully disappeared from the islands like cougars have (although they have been known to swim between islands).

Justin Suraci checks motion-activated speakers in the field on Penelakut Island. Photo by Jude Isabella

But aside from occasional visits from campers with dogs, Portland Island raccoons live a secure life. So how do these fearless island raccoons affect the food web?

From Clinchy and Zanette’s earlier research on songbirds, Suraci and his colleagues already knew the island raccoons feasted on terrestrial species, particularly songbird eggs during bird breeding season. Across several islands the team discovered that even populations of relatively big, smart, and aggressive birds, like crows and ravens, suffered on islands with raccoon predation. And what about marine life? It’s bad.

Suraci sits on the side of the boat not far from Lamalchi Bay and marks a red rock crab, attaching a little plastic bead to an appendage before releasing the crustacean back to the ocean. These crabs follow the tides, preferring life beneath the waves. Raccoons, however, will wade up to their bellies to hunt crabs, a behavior that has an effect even beyond the intertidal zone. By tracking the crabs, Suraci has found that raccoons prefer smaller red rock crabs—on average 8.3 centimeters across the carapace, three centimeters smaller than the legal harvest size under British Columbia’s shellfish harvesting regulations. Under those same regulations it’s not legal to harvest females, but, of course, these regulations mean nothing to raccoons. They naturally prefer smaller crabs, and since females are smaller than males, they harvest females disproportionately. Overall, the presence of the bandits on the beach leads to 50 percent fewer red rock crabs, and up to 90 percent fewer shore crabs.

Rapacious raccoons put biodiversity at risk. In an ecosystem with a top predator, raccoons would normally act like prey and fret about survival. But fearless raccoons eat almost nonstop, unseemly behavior for a mesopredator. They also forage during the day, unusual for a nocturnal animal.

Watch Portland Island raccoons for even a few minutes and they seem like they’re asking for it. They forage far from cover in the intertidal zone, barely watching for danger while ripping apart crabs. These furry felons treat the intertidal zone like an all-you-can-eat, limited-time seafood buffet: at low tide, the raccoons speed-slurp worms, pricklebacks, toadfish, red rock crabs, shellfish—messily jamming gobs of flesh into their mouths.

“If you just look at that very simply, they have twice as much time to spend foraging so they’ll have twice as much impact on their prey if they’re foraging night and day,” says Suraci.

If a cougar appeared, however, the clueless raccoon tucking into breakfast would never make it to the shelter of the trees over 100 meters away. Raccoons are slow and awkward runners; they would never outrace a cougar, wolf, or bear.

But are the Gulf Island raccoons reckless? Not if, as Clinchy and Zanette showed in their song sparrow study, these relaxed, well-fed islanders have more surviving young than their more fearful counterparts, those living with wolves and cougars in places like the remote, west side of Vancouver Island, a large island between the Gulf Islands and the Pacific Ocean.

Clinchy and Suraci have now begun studying raccoons on the west coast of Vancouver Island in Clayoquot Sound, comparing populations there with those on predator-free Gulf Islands. A Parks Canada analysis of cougar and wolf scat from the Clayoquot Sound area revealed that raccoons can comprise close to 28 percent of a cougar’s diet and 23 percent of a wolf’s.

The scientists found that raccoon density in the two sites differed markedly. On the Gulf Islands, they observed nine times as many raccoons per kilometer at night, and 18 times as many during the day than at Clayoquot Sound. The data suggests that predators keep raccoon numbers down, certainly by eating them, and perhaps by scaring them too, nudging them toward more cautious behaviors. A scared response, after all, can exact a biological price.

A number of raccoons forage simultaneously in Portland Island’s intertidal zone. Almost the same color as the boulders they scramble among, these raccoons are smaller and blonder than their city cousins. Photo by Shanna Baker

“With the sparrows, we demonstrated that cost,” Clinchy says. Having fewer chicks is a big price to pay. So it makes sense that once freed from the pressure of a predator, an animal loses its fear response, can forage more, and produce more offspring.

In the end though, the ecosystem bears the cost of island raccoons gone wild on prey.

Clinchy, Suraci, and Gray spend hours this June day on Penelakut Island. A raven calls, float planes drone overhead, boats zip by, the tide edges up, and the smell of a coastal summer hangs in the air: a tang of saltwater creeping over the pungent tidal greens. Today Penelakut is just a wild laboratory for the scientific team hurrying to finish a day’s work.

The trio throws another curveball at the raccoons, adding scent cues to the sound cues. On the 200-meter stretch of beach where they’ve hid monitors that play recordings of barking dogs (either scheduled or activated by the motion of a raccoon), Gray squirts wolf urine into containers capped with perforated lids, which she then hangs off tree branches at the shoreline’s edge. At another beach—where the team will use sound and scent cues of animals that are not raccoon predators—they broadcast the sounds of seals and hang containers filled with rabbit urine.

Suraci and Gray return regularly to measure and count raccoon prey over the next three months. By the end of the summer, their data indicates that if the community on Penelakut wants a shellfish industry they need scaredy-pants raccoons—raccoons that act like mesopredators.

On Portland Island, at the end of summer, Clinchy stands on a beach looking through binoculars. A slightly sulfuric, greens-gone-bad smell, pervades the air. Five raccoons with light fur, crisscross a mucky carpet of seaweed, wading into the water to fish for crabs.

“This is a death zone!” Clinchy says, crouching to pick up one of many crab carcasses, legs, and claws nestled in the carpet of seaweed. “This is a fresh kill, see the blood?” He tips the crab carapace and an orangey-red liquid sloshes around.

Illustration by Mark Garrison

Closer to the trees, almost the same color as the boulders they scramble among, are a mother raccoon and a couple of kits, foraging, keeping some distance from the other raccoons. The Portland Island raccoons are smaller and blonder than their city cousins.

Research into the ecology of fear is in its fourteenth year on the island. Graduate students continue the work with a range of experiments, what behavioral ecologist David Westneat might call nibbling around the edges of behavioral ecology. One study focuses on whether the offspring of scared mother song sparrows have poorer survival rates. Other researchers have their eyes on mice, assessing the rodents’ foraging behavior when they hear recorded calls of predatory owls.

The next day Clinchy is off to England, along with Zanette, to spend a few months working with Oxford University’s Wildlife Conservation Research Unit. Researchers there ponder the same kind of questions as Clinchy and his colleagues do in Canada, but they work with different animals, such as the European badger, another mesopredator without a population of wild apex predators. The Canadian scientists will bring their expertise, along with their sound recordings and the urine of wolves and bears—natural predators of badger but now extirpated in England—to test the badger’s fear response.

In late fall, Suraci takes a quick trip to Portland and a neighboring, privately-owned island called Tortoise. He’s smeared cat food on rocks to lure raccoons to spots where cameras hidden in the trees will catch them reacting to the sounds coming from motion-activated speakers hanging nearby. Suraci swaps out memory cards from the cameras and checks the playback speakers, a newer version of the ones he erected on Penelakut. On Tortoise he checks the footage of one camera where the motion of a raccoon would also activate a recording of a dog. Suraci laughs when he watches footage of a brazen raccoon that perked up at the sound of a barking dog. The raccoon seemed startled, and began to run, but thought better of it, and turned back—a quick grab for food was worth the risk.

No fear, no limits. Maybe the raccoon is Icarus, flying much too high.

Follow ecologists Mike Clinchy and Justin Suraci in the field as they study the effects of raccoons foraging in the intertidal zone on predator-free Gulf Islands.

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Cite this Article:

Cite this Article: Jude Isabella “Bandits on the Beach,” Hakai Magazine, Apr 22, 2015, accessed June 21st, 2024, https://hakaimagazine.com/features/bandits-beach/.

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