A creeping plague of crickets is hitched to everything in the world

  • Mormon cricket drawing

    David Wilson

There have been a few times when my love of nature has been put to the test: a July 4 snowstorm that trapped me in a tent for three days, a two-month bout with poison oak, a gnat attack in Utah. The Mormon cricket plague was no exception.

The outbreak began in 1981 in Dinosaur National Monument on the Colorado-Utah border. The flip of some mysterious biological switch transformed solitary emerald-green crickets into bigger, black, very social pests. First, they gathered into bands by the tens of thousands. After a few years, millions were floating across the Green and Yampa Rivers and invading range and crop land.

It was not a sight for the faint-hearted.

Mormon crickets, which are actually flightless grasshoppers, climb vertical cliffs and houses, munch through an occasional crop field, and drop into wells, where their decaying carcasses pollute livestock water supplies. Where they cross roads, their squashed bodies create hazardous slicks. And to the horror of drivers who stop to see what they are skidding on, crickets can be observed eating their fallen fellow travelers.

I got to Dinosaur in 1987, the year the plague peaked, to take a summer job with the monument's peregrine falcon recovery team. At that time, the peregrines were making a gradual comeback after decades of poisoning by the now-banned pesticide DDT.

Shortly after I arrived at the monument, I was given what should have been a plum assignment - to confirm a visitor's sighting of a new pair of peregrines in the remote upper reaches of the monument's Yampa River canyon. If the birds were found, it would be the monument's first new pair in several years, and a signal that the peregrine was coming back.

There was only one problem with the assignment: It was in the heart of cricket country. I stepped down from the truck into a dense, endless mass of crickets. One on one, I found Mormon crickets fascinating. But all together - marching to their primitive beat, spitting dark juice, roosting by the thousands in a single tree or crushed beneath the tires of the truck - I was repulsed. I thought of the Mormon cricket plague the way I thought of poison oak: Is this truly necessary?

I pulled my socks up over my trouser bottoms - lest a bold cricket venture up a pant leg - and set up the spotting scope. Along with three Colorado Division of Wildlife field biologists, I was to spend two days on the edge of the canyon, scanning its precipitous depths for the falcons.

The job demanded that I concentrate. The crickets were there to make sure I couldn't. They climbed up my pants. Spat juice on my notebook. Crawled into my rucksack. Since they would not be ignored, I began feeding them bits of Ritz crackers, the crickets' strong jaws making short work of them. My revulsion evolved into curiosity, which, a few crackers later, turned to tedium. In a cruel moment, I flicked a cricket off the 1,000-foot cliff on which I was sitting. It landed unharmed 15 feet below on a serendipitous ledge, which it soon left to climb the vertical face back toward my perch. A bit of cracker, my sorry offer of peace, awaited it.

Some say it is easier to wipe out humans than crickets. Indeed, there has been only one instance of successful cricket control. Seagulls are said to have swooped down and eaten the pests during the legendary outbreak of the mid-1800s, saving the crops and perhaps the lives of the Mormon settlers of the Great Salt Lake Valley of Utah.

In the Dust Bowl years, Mormon crickets razed drought-stricken crops and overgrazed rangeland. Doug Chew, a veteran Utah rancher, talks of crickets eating a saddle right off his corral fence, leaving only the metal stirrups behind.

During my summer at Dinosaur, local ranchers, fearing a repeat of the Dust Bowl years, asked the Department of Agriculture to control the crickets. The department's Animal and Plant Health Inspection Service sent planes filled with Sevin-4 oil, a potent pesticide. Large numbers were killed, but even Otha Barham, head of the operation, admitted that the crickets were going to march until their mysterious biological switches turned off again.

While the crickets had a good chance of surviving the spraying, my boss, Steve Petersburg, chief of the monument's Natural Resources Division, was not so sure the peregrines would. The National Park Service had been challenging the spraying, citing studies that indicated Sevin attacks the nervous system of songbirds that ingest the pesticide while eating poisoned crickets. Petersburg claimed that since the peregrine fed heavily on songbirds, the spraying was poisoning the raptor's food supply.

Concern intensified when a pair of falcons were found dead after intensive spraying. Petersburg said it was a "crying shame" that, just as the falcons were overcoming the effects of DDT, they were falling victim to Sevin.

Like Petersburg, Chuck MacVean - an entomologist from Colorado State University - was a good spokesman for the crickets, for unlike most of us, he gloried in them. At his trailer-turned-lab, parked in the small town of Dinosaur, Colo., MacVean had his collection of crickets, a centrifuge in which he made extractions of crickets to determine the presence of parasites, and his freezer - a veritable cricket morgue.

MacVean said that during the Dust Bowl years, drought and overgrazing rendered the Great Plains barren; crickets only made things worse. In years of average rainfall, there is enough vegetation to keep both cows and crickets happy. Overall, his two-year study found that cricket grazing has no significant effect on livestock grazing, largely because Mormon crickets mostly eat plants that cattle don't like.

I pondered all this as I lay in my sleeping bag after the first vain day of searching for the peregrines. While phantom crickets nibbled at my feet, I contemplated the numberless stars above and the numberless crickets below. I decided I could tolerate a cricket for a bedfellow if it meant the peregrine falcon could continue its recovery.

The next morning, I walked out to my observation point, the crickets already descended from their nightly roost in the pinyon and juniper trees. The day promised to be a hot one, and without a peregrine in sight, a frustrating one as well.

Just as I readied to brush a wayward cricket off a pantleg, I heard a shout. Someone had found the falcons, a juvenile male and a mature female soaring through the sandstone canyon below. Although they weren't old enough to breed, it was a new pair. Given half a chance, the peregrine falcon would once again rule the canyons.

As I watched the birds scanning the canyon for prey my textbook understanding of ecology was transformed. I still get annoyed by gnats, I wonder about the purpose of poison oak, and I can still be grossed out by crickets cannibalizing each other. But I no longer question whether such pests have a right to exist.

"When we try to pick out anything by itself, we find it hitched to everything else in the universe," John Muir wrote. During that summer in Dinosaur National Monument, the ties that bind crickets, and songbirds, and falcons, and me became visible. If we eliminate the bothersome, ugly or insignificant, we also destroy that which we hold dear.


The cricket plague has diminished over the years, although isolated bands return each spring. Some ranchers near Dinosaur still want to spray, but settlement of a lawsuit filed by the National Parks and Conservation Association and the Sierra Club halted spraying for crickets within 10 miles of a peregrine nest.

This means quite a bit of the monument is off limits. From 1987 to 1994, the number of peregrine pairs increased from four to 15. While the USDA inspection service still kills crickets, it relies mostly on pesticide-laced ground bait on cricket egg beds rather than on aerial spraying.

Dena Leibman now lives in Washington, D.C., where she is editor of Friends of the Earth newsmagazine.

A version of this article appeared in Indiana University Alumni Magazine.

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