As the sun rose over the Mojave Desert, researcher Kristina Drake approached with caution as a creature with weary eyes, a scuffed carapace and skin as rough as rhino hide peered at her from the edge of a dirt road just east of here.
Wearing rubber gloves, Drake picked up the old female California desert tortoise and, in one fluid motion, moved her to safer ground beneath a nearby creosote bush. “It’s one of ours,” she said. “No. 4118.”
The tortoise, nicknamed “Road Warrior,” was among the 760 captured and airlifted by helicopter a month ago out of the southern portion of the Army’s nearby National Training Center at Ft. Irwin, which is slated for expanded combat exercises. Her well-being in new terrain is essential to the $8.7-million relocation effort, which has been hit hard by a problem unforeseen by federal biologists: rampant coyote attacks.
“Coyotes didn’t seem to be a problem when we started,” said U.S. Geological Survey biologist Kristin Berry, a lead scientist in the project. “The question in the back of all of our minds now is this: How could we have determined that this was going to happen?”
The California tortoise, whose population has fallen to an estimated 45,000 on the public lands in the western Mojave, is protected under state and federal endangered species acts.
In 2001, Congress authorized Ft. Irwin to expand into prime tortoise habitat. As mitigation, the Army agreed to move the tortoises from the expansion area onto unoccupied public lands, an effort that began in late March.
So far, at least 14 translocated adult tortoises and 14 resident tortoises in the area have been killed and eaten by coyotes, according to biologists monitoring survival rates of the reptiles, most of which were fitted with radio transmitters. In a related problem, 15 of 70 baby tortoises collected at the training center as part of the relocation have died of various causes, Army officials said.
The problem, they say, may be linked to severe drought, which killed off plants and triggered a crash in rodent populations. As a result, coyotes, which normally thrive on kangaroo rats and rabbits, are turning to the lumbering Gopherus agassizii for sustenance.
In an effort to prevent further losses, the Army has requested that the predators, described by one military spokesman as a “rogue clan of coyotes,” be eradicated by animal control sharpshooters. The gunners, however, have been delayed for weeks by bureaucratic red tape, military officials said.
In the meantime, many translocated tortoises have shown a tendency to wander, sometimes for miles, often in a northward direction back toward the Army base. Gashes and tooth marks on the shell of a translocated tortoise found April 15 indicated that it had been ripped out of the front of its carapace.
The Center for Biological Diversity, a Tucson-based environmental group, said it plans to file suit later this month against the Army, the U.S. Fish and Wildlife Service and the Bureau of Land Management for allegedly violating the federal Endangered Species Act in their management of desert tortoises.
Desert tortoises spend most of their lives underground. Recent studies indicate that the creatures, which can live for a century, are extremely sensitive and have complex social lives.
Of particular concern, lawyers for the center say, was the Army’s decision a month ago to move tortoises to areas where they would be vulnerable to potentially lethal threats. The Army had been warned that numerous environmental studies expressed concern about vehicle traffic, drought-stricken foraging grounds, and resident tortoises suffering from infectious respiratory disease and predation by ravens, dogs and coyotes.
“The deed is done, and now we are watching the aftermath,” said Ilene Anderson, a biologist and spokeswoman for the Center for Biological Diversity. “It’s a disaster. We’ve lost so many tortoises -- the California state reptile and a species that has taken a nose dive over the past 20 years -- so early on in the project.”
Michael Connor, a longtime advocate of the tortoise and California science director of the Western Watersheds Project, a nonprofit conservation group, was critical of the Army’s plan to wipe out suspect coyotes.
“These aren’t rogue coyotes. They’re just coyotes trying to make a living in the desert,” Connor said. “Now they want to shoot them. Fine. But what happens if there are unforeseen implications from wiping out the region’s top predator, like an explosion of rabbits and rats?”
Beyond that, he added, “the U.S. Fish and Wildlife Service had identified canine attacks as possible threats even before the project got underway. So I’m surprised the scientists are surprised that tortoises are becoming targets.”
In any case, William Boarman, an adjunct professor of biology at San Diego State who’s helping direct the translocation project, said that after the Army decided to expand operations at Ft. Irwin, “we were stuck with bad options: move the tortoises or leave them in place, which would have been much worse.”
“Translocation was always risky,” he added. “We’re trying to make it work the best we can, and conduct research that can help us make future translocations more effective.”
In years to come, the Army plans to relocate an additional 1,200 tortoises from the western edge of the base to prevent them from being squashed by military equipment.
Field researchers said most of the predation has occurred in areas between the rugged Calico Mountains and desolate Coyote Dry Lake.
On a recent weekday morning, USGS field researcher Kevin Lucas strode across loose rock and cholla cactus in a sandy wash just north of the lake near where a hefty radio-collared male tortoise, variously known as “No. 4164" and “Thor,” relaxed in a patch of shade.
That tortoise was among the lucky ones.
“There was another translocated tortoise I’d really gotten to like, even admire,” Lucas said. “He was a tremendous mountain climber with a can-do personality.
“The last time I saw him, he was on a steep slope in howling winds and something didn’t look right,” he recalled. “Through binoculars, I saw that his head and legs were missing. A deep sadness came over me.”