ByJessica Baltzersen
Published January 18, 2024
In the winter of 1924, 14 American bison weighing 1,500 pounds arrived in crates at the harbor of Santa Catalina Island, off the coast of Los Angeles, California, where they were set free to roam the hillsides.
Local lore has it that they were brought here to film a movie, though there’s little evidence they made a Hollywood debut. But over the last century, the bison have become the unlikely stars of Catalina’s ecosystem.
It’s unclear how much longer that will last. The herd that once numbered as high as 524 is now stunted at 90 and no longer reproducing. While some argue the bison are integral to the island’s cultural identity, others point to the ecological concerns of allowing this invasive species to remain.
Now Catalina stands at a crossroads, facing a complicated decision on what’s best for the bison, its critical ecosystem, and its human residents.
Why are there bison on Catalina?
Bison are not native to the Mediterranean climate of the 75-square-mile island that sits off the coast of Southern California.
Why the bison were brought to Catalina is still shrouded in uncertainty with several contradictory tales. The most common—which can be recited from memory by most Catalina residents—is that 14 bison were transported to the island for the production of Zane Grey’s western film, The Vanishing American.
(Bison or buffalo? Possum or opossum? What’s the difference?)
“The stickler of it all is there are no bison in that movie,” says Gail Fornasiere, deputy director of external affairs at the Catalina Museum for Art & History. “The story for a long time was [the bison scenes] must have made the cutting room floor. But a good chunk of that movie was filmed in Arizona… so it doesn’t make any sense.”
Still more theories abound. In 1938, the Catalina Islander recounted the famous stampede scene in another Grey movie, The Thundering Herd, claiming it was captured on Catalina; however, a 1925 New York Times article says the scene was filmed in Yellowstone National Park. Neither can be confirmed, as the film reels remain missing to this day.
“It’s still a little bit of a mystery,” Fornasiere says, “and probably always will be.”
One of many problematic invasive species
“There’s not too many places on this planet that are better than Catalina Island,” Lauren Dennhardt says, as we approach a vista with sweeping views of a sparkling Pacific Ocean.
Dennhardt is the senior director of conservation at the Catalina Island Conservancy, the nonprofit that manages 88 percent of the island’s 48,000 acres. Catalina, the southernmost of the Channel Islands, is geologically pivotal in preserving biodiversity that exists nowhere else on the planet, including the Catalina Island fox and the Catalina Island mountain-mahogany, the rarest tree in North America.
But the island’s biodiversity has faced a growing threat ever since the 19th-century ranching industry introduced cattle, horses, sheep, and other non-native herbivores to the fragile ecosystem.
(What are invasive species—and how can we control them?)
The most notorious of these newcomers were the mule deer, which arrived in the 1930s. The deer, which are managed by the California Department of Fish and Wildlife (CDFW), are wildly overpopulated and suffering from dwindling resources—while in turn causing extensive habitat destruction and threatening the island’s unique and endangered species.
The Conservancy initiated a plan in 1990 that eradicated 12,000 feral pigs from the island and 8,000 feral goats by 2004. Recently, the Conservancy proposed a similar plan—still being reviewed by the CDFW—to kill the island’s 1,800 deer as a last resort under a major restoration project.
But one ungulate remains unaddressed on the island—the bison. And their future is a little more uncertain.
An on-again, off-again relationship
When William Wrigley Jr.—the chewing gum mogul and owner of the Chicago Cubs—purchased Catalina Island in 1919, he invested millions to make it a premium resort destination with a vision for what he referred to as a “playground for all.”
After it was agreed the bison would remain on the island, he acquired 10 more in 1934.
As the herd grew, so did the enthusiasm from island residents who revered the giant grazers as a symbol of the island. In the 1950s, stores sold gold-painted bison dung referred to as “buffalo chips.” And in the 1970s, bartender Michael Hoffler of Two Harbors is credited with inventing the Buffalo Milk cocktail.
(How the return of bison connects travelers with Native cultures.)
Eco tours and bison expeditions have also been offered for decades, and the bison can be found in gift shops everywhere as stuffed animals and figurines and plastered on t-shirts, keychains, and books.
“The bison have become this link with the island,” Fornasiere says. “The residents are very protective and proud of their history.”
Their celebrity status has set the bison apart from other invasive ungulates—except for their impact on Catalina’s ecosystem.
While the bison do help keep back some of the invasive grasses, Dennhardt explains that they create wallows and cause erosion. Other scientific studies have attributed the impact of bison activity to reducing plant diversity, damaging endemic plants and tree species like oak trees, and spreading non-native plant seeds through their hirsute coats and droppings.
The bison themselves also began to suffer.
“Twenty years ago, the major problem the managers were having was overpopulation, and the bison weren’t doing well,” says James Derr, a professor in the department of veterinary pathobiology at Texas A&M University. “The bison weren’t getting enough to eat. They were pretty skinny-looking animals.”
Determining a strategy to control the herd’s population has proven to be particularly challenging.
Controlling the bison population
Early efforts to manage Catalina’s bison dovetailed with a nationwide initiative to restore thundering herds to their ancestral lands in the Great Plains—where only 350,000 bison remain of an estimated 30 million that roamed in the mid-1800s.
From 2002 to 2004, the Conservancy repatriated Catalina herds to the Lakota Indian reservation, Cheyenne River and Standing Rock Lakota Indian reservations, and Rosebud Indian Reservation.
Unbeknownst at the time, however, the animals were not actually purebred bison. A study from the University of Southern California and Texas A&M University revealed in 2007 that 45 percent of the bison they sampled contained domestic cattle mitochondrial DNA.
To keep mainland bison as “pure” as possible, it was recommended that the Catalina bison no longer be reintroduced to natural populations. Instead, the Conservancy resorted to a five-year experimental birth control plan in 2009, injecting female bison with the contraceptive porcine zona pellucida.
Now, the bison aren’t reproducing at all.
With a declining population and an ever-present threat to the island’s habitat, multiple different management strategies have been proposed with no clear-cut answer. A 2005 study developed different options for consideration such as managing a “relatively small bison herd” and restricting them to smaller portions of the island.
In the meantime, the bison—which are significantly smaller than their mainland counterparts—receive supplemental water troughs and hay to help them cope with ongoing droughts and nutritionally poor conditions.
But not everyone agrees that the herd should remain on the island at all—and some argue the bison are not as essential to the island’s economy as it may seem.
“Less than 10 percent of visitors to the island make their way into the interior,” Calvin Duncan, a former wildlife biologist at the Conservancy told National Geographic in a statement. “A survey conducted on the island found that less than half of new visitors were aware that bison were present on the island, and more than half of all visitors surveyed stated that the presence of bison in the interior would not influence their desire to purchase an interior tour.”
“If the ecological integrity of the island, human safety, and the welfare of the bison themselves are given the highest priority, a significant reduction and restriction of the Catalina bison population, or its complete removal, should be considered,” writes Duncan.
Currently, no decisions have been made about the bison’s future management plans, but the issue is reevaluated every year. It’s a decision that Dennhardt says has “moral and ethical considerations” and one that needs to be both “thoughtful and informed.”
So what’s to become of this hundred-year-old island herd? Only time will tell.
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