A group of ratters on Lord Howe Island, holding their kill by the tail. (Photo: Courtesy of the Lord Howe Island Museum)
When the Lord Howe stick insect limped back into the limelight from the brink of extinction 15 years ago, the event sparked renewed celebrations of biodiversity on Lord Howe Island, the insect's native home off the east coast of Australia. Tributes to the charismatic “tree lobster” or “walking sausage” proliferated and even included an animated documentary featuring “Sticky”as the lead. Yet behind every fêting of Lord Howe’s endemism lurks an uninvited guest: Rattus rattus, the common black rat.
Over the past century, Lord Howe Island residents, the local state government, and even the U.S. Department of Commerce—aided by a flock of barn owls—have waged a multipronged, multispecies war on these invasive rats.Their efforts were united in the name of ecological and economic protectionism, with one species in particular garnering the most attention: the kentia palm.
Lord Howe Island, off the east coast of Australia. (Photo: Public Domain)
Whereas black rats have staked a claim to every continent on the planet, the elegant kentia palm (Howeaforsteriana)is native only to Lord Howe. Originally known as the “thatch palm” for its use in thatched roofing in island homes, by the late 1800s the kentia had become a horticultural icon and specimen plant for greenhouses and ballrooms around the world, an accolade that endured well into the 20th century.
“Society in every civilized city of the world demands these palms for decorative purposes,” wrote the Los Angeles Times in 1929. “These dainty little palms in pots and tubs give a freshness and grace to every occasion.” Unlike tropical palms, kentias evolved in Lord Howe’s temperate climate, rendering them adaptable to lower humidity, less light, and cooler temperatures—prime for export to the Western market.
Foliage and palms on Lord Howe Island. (Photo: Ian Cochrane/CC BY 2.0)
Ecological disaster struck Lord Howe on June 15, 1918, the day the SS Makambo ran aground near Neds Beach and wallowed for over a week. While repairs were made to the vessel, stowaway rats drifted aboard flotsam and jetsam towards the beach. Once ashore, they discovered a cornucopia of tasty delights: land snails, spiders, the eggs of flightless birds, and every endemic morsel in between. To date, rodents are credited with the extinction of five species of birds and 13 invertebrates on Lord Howe, and would have been guilty of exterminating the giant stick insect had a handful of the limby creatures not survived beneath a bush on Ball’s Pyramid, a razor-sharp volcanic stack 12 miles southeast of Lord Howe.
A Lord Howe Island stick insect. (Photo: Granitethighs/CC BY-SA 3.0)
For the palm industry, the arrival of rats was devastating. “The seeders quickly noticed that the rats were eating the green seed at a rate of knots,” says islander Jack Shick, who comes from a long line of palm harvesters and now operates Sea to Summit Expeditions, a fishing and hiking outfitter. Indeed a contemporary article in the Royal Botanic Gardens’ Kew Bulletin, reveals that in the seven years following the rats’ arrival, the palm crop was decimated by a whopping 80 percent, from 4,494 bushels in 1919 to just 877 bushels in 1925.
To protect their livelihoods and the palm seed business, the Lord Howe Island Board distributed light shotguns and levied a bounty on the rats, prompting many islanders to moonlight as ratters. At six pence per tail, “a reasonable living could be made ratting with a couple of terrier dogs and a shotgun,” wrote local author Kerry McFadyen in her book Pinetrees: Lord Howe Island 1842-1992.
Payment for culled rats came intermittently, but stockpiling dead rats until payday in a subtropical climate was a stinky proposition. More often than not, hunters would remove rat from tail, trash the former and organize the latter in matchboxes. In essence rattails became an alternate currency. (One probably apocryphal story tells of a family slipping a bundle of rattails into the offertory at church in lieu of coins.)
Bundles of rats' tails, organized into matchboxes. (Photo: Courtesy of the Lord Howe Island Museum)
Jack Shick grew up hearing the ratter lore from his elders, many of whom kept fox terriers (“foxies”) for rat hunting. “The dogs would find a burrow, then the hunter would screw up some fiber from the palm tree and light a fire in it. The flames were fanned with an old hat to force smoke down the burrow. The dogs would wait at the exits until the smoke became too much and the rats would run out... into the waiting mouth of a dog!” If the rat tried to escape his smoky grave by scampering up a tree, the hunter would be ready with a shotgun.
Anticipating that the rat-hunting bonanza might need a boost, in 1927 the U.S. Department of Commerce dispatched a flock of barn owls from San Diego to Lord Howe. (At the time California nurseries were a major importer of kentias.) There the American owls joined the raptorial ranks of Australian barn owls and Tasmanian masked owls, fellow draftees in the war on rats.
American newspapers covered the event with bellicose glee: “Native Owls Off to War On Rats,” wrote the New York Times, while The Washington Post praised the owls’ fearsome “war hoot.” It wasn’t just the palm seeds that the owls were meant to rescue, but the people whose livelihoods depended on the sale of those seeds. “It is up to the old-time barn owl to play the hero then and save the inhabitants,” wrote the Post.
Thanks to the combined efforts of both ratters and owls, the seed harvests leapt from a paltry 955 bushels in 1926 to 3,037 bushels the following year. The owls were effective if indiscriminate mercenaries in their hunting of both rats and flightless woodhens. (The Post somewhat presciently surmised that if the owls were successful, the islanders might find themselves in the “embarrassing position of having to shoot their benefactors.”)
The view across Lord Howe Island. (Photo: patchtok/CC BY 2.0)
In the years following World War II, the trade in palm seeds took a backseat to the blossoming tourism sector, and the focus on pest control shifted from palm protectionism to conservation of Lord Howe’s delicate biosphere as a whole. By the 1940s steel spring-back traps were commonplace, and in the 1950s the aptly named warfarin rat poison came on the scene.
Today the rodenticide coumatetralyl is used at roughly 2000 bait stations scattered through the settlement area. “The rats have the other 90 percent of the island to roam and wreak havoc on seeds, roots, lizards, bird eggs, birds, beetles, snails, spiders, etc.” says naturalist and author Ian Hutton, who has written several books on Lord Howe’s endemism and leads eco-tours of the island.“This is why a rodent eradication proposal is being looked at now.”
In 2017, an ambitious aerial-baiting program will launch with the goal of ridding the island of rats once and for all and restoring balance to the island ecosystem. “The driver for rodent eradication all along has been to protect the island’s biodiversity,” says Hutton. “The economic benefit of palm seed protection was just the initial carrot.”
Lord Howe Island may soon be free of the chronic threat of rodents, just in time for the centennial anniversary of the stranding of the SS Makambo and the arrival of rats on Lord Howe. It only took a hundred years’ war.