By Linda McK.Stewart
Operation Rescue on Anacapa
Atop the cliffs of Anacapa it’s a 360-degree view of infinite sea, infinite sky.
From the human perspective, the island of Anacapa is all straight up, straight down and relentlessly rocky in between. Its skies belong to gulls, pelicans and steely-eyed raptors. Its skimpy, stony beaches belong to harbor seals and sea lions.
All year round the only unvarying constant is the wind. Though the surrounding sea may be silky smooth, atop the cliffs of Anacapa the winds bluster, sigh and twirl but never relent.
Only 12 miles off the California coast, Anacapa – plus its neighboring islands, San Miguel, Santa Rosa, Santa Cruz, and Santa Barbara – make up the Channel Islands National Park. The distinctive ecosystem that has evolved on each island has been shaped primarily by isolation, time and evolution. Stewardship by the National Park Service seeks to safeguard the delicate balances by which each island’s ecosystem is composed.
Thanks to a hospitable combination of climate, sea currents, topography and latitude, Anacapa, smallest of the Channel Islands, has served more than 70 species of birds since time before memory, some of them unique to California. For dozens of different migratory species Anacapa is the ideal feeding and mating ground, rookery, way station, refuge and resting place. A sweet harmony long prevailed on the island whereby the tiny island fox, the spotted skunk and the deer mouse happily coexisted with their feathered neighbors. Strict rules regarding human incursions assured island-wide tranquility.
But then in the 1990s came disquieting reports by park rangers of a sharp decrease in certain bird populations. The Western gull, Scripp’s Murelet, Xantu’s murelets, Cassin’s aukelets – all island regulars – were disappearing. Something had tipped the balance of nature, but what? All of the diminishing species were ground nesters, a good clue right there. Intensive investigations soon found the answer and a nasty answer it was – rattus rattus, aka rats.
With alarming speed a burgeoning rat population was taking over life on Anacapa. Bird nests were being invaded, eggs eaten before they could hatch, newborn foxes and skunks consumed shortly after birth. The park service was baffled. Why was the island’s bird population, long stabilized, now tipping toward threatened extinction? Rats were not indigenous to Anacapa.
What was going on?
On Dec. 2, 1853, the SS Winfield Scott, a steam propelled side-wheeler, departed San Francisco heading for Panama. Traveling at full throttle down the fog-bound Santa Barbara Channel just before midnight, she slammed full tilt into the rocks that encircle Anacapa. A luxury vessel, she carried 465 passengers, $800,000 in gold, several tons of mail, a full crew and a hold-full of stowaway rats.
Thanks to the calm demeanor of her skipper, no life was lost. The boat broke up on the rocks. The passengers were rescued. The cargo was saved, as was the mail. As for the rats, they easily made it to shore and, safe from predators, spent the next century and a half vigorously procreating.
The task confronting the National Park Service was formidable and fraught with political land mines: How to restore the natural balance of life on Anacapa and in the process save several bird species from extinction?
Finally a plan of action emerged. First came several years of painstaking research. Exactly which bird species were being attacked? Statistically, to what extent were their numbers being reduced? How rapidly was the island habitat being altered? To amass such precise and voluminous information, the NPS made good use of hundreds of volunteers, some students from the California universities and many longtime bird watchers. They fanned out across the island, banding birds, deer mice, the unique, small (5- to 6-pound) foxes and spotted skunk. Cameras were strategically placed as well as listening devices to record birdcalls.
Then came a huge gathering of non-rat wildlife. As many foxes, skunks and field mice as possible were collected and taken into custody. That was followed by a mid-winter dissemination of a powerful rodenticide. By helicopter, slingshot and manual broadcasting it was projected into all the inaccessible cliffside caves, hollows and rocky crevices and across the flatland of grasses and woody shrubs.
It was a massive, formidable project. As Kate Faulkner, biologist with NPS explained, “99.09 percent effectiveness was unacceptable. In just one year a single pair of rats can produce 5,000 offspring. We had to kill every single one, no exceptions.”
This spring, NPS once again welcomed an exuberant crowd of visitors, press included, to Anacapa to view the happy result of the experiment that cost some $3 million, much of it provided by conservation groups. The bright yellow coreopsis that grows rampant on Anacapa was at its exuberant best. Brown pelicans, only recently facing extinction, swooped and dived, noisily competing with the Western gulls that strutted and preened in the springtime grasses.
“It’s estimated that worldwide, 80 percent of all bird extinction is caused by rats,” Faulkner told the group.
No one speaks or even considers the worldwide elimination of rats. But at least on Anacapa, in California’s Channel Islands, rattus rattus has been, at least for now, triumphantly defeated.
IF YOU GO: For details about full- and half-day trips to the Channel Island National Park call 805-658-5730.