Long-Living Tortoises Roam Protected Portion of Mojave Desert

Desert tortoise

By Renee Eng
Spectrum News

CALIFORNIA CITY, Calif. — In the Mojave Desert, it’s not uncommon to see rabbits or even rattlesnakes slithering around but one reptile that’s harder to spot is the desert tortoise. But it turns out there are plenty of them in a protected area just an hour north of Palmdale, outside of California City. It’s called the Desert Tortoise Natural Area.

Video

“They are a long-lived species,” explained Jillian Estrada, preserve manager and conservation coordinator for the Desert Tortoise Preserve Committee.

“They can live more than 100 years in captivity. We actually see several tortoises out here that were initially tagged in the early 70s as part of a long-term study.”

We spotted one male tortoise that Estrada estimates is at least 40 to 50 years old. Her work with the DTPC focuses on protecting the long-lived reptile in the natural area.

“It’s about 39.5 square miles so just over 250,000 acres,” said Estrada.

The property was set up in the 1970s with the Bureau of Land Management and is filled with about 1,000 tortoises.

“They have inhabited the Mojave Desert for millions of years,” described Estrada. “They have been part of this ecosystem. They are specially adapted to survive here.”

But their survival is threatened by human settlements and a raven population that’s grown by 1500 percent over the last 30 years.

“They’re generalists, they’ll eat anything,” said Estrada. “They eat baby tortoises, adult tortoises, baby birds. They will eat lizards.”

A generous appetite threatening baby tortoises that don’t have a fully formed hard shell. It can be easy for predators, especially ravens, to peck through their brittle shells.

“As the mortality rate of juveniles has increased, in large part due to raven predation, we’re not seeing as many females surviving to reproductive age,” said Estrada.

The reproductive age for female tortoises is about 15 years old. However, the raven threat remains as those birds are protected under the Migratory Bird Act.

Tortoises that do survive, visitors can spot in the protected area but they cannot touch them. The animal – which is California’s state reptile – is protected at both the state and federal level.

Desert tortoises also hide out for about half the year.

“From late fall to early spring, about five to six months out of the year these guys are hibernating, which for these guys is called brumation,” said Estrada

When they’re not brumating, tortoises will dig shallow burrows, coming out to look for food. Visitors can learn more about their habits at an interpretive kiosk or explore four guided trails that total about 3.5 miles.

There’s also a full-time naturalist on-site from the middle of March to early-June to lead hikes and teach visitors about these gentle creatures.

The Desert Tortoise Natural Area is open daily from 8 a.m. to 5 p.m. and is free to the public.

EDITORIAL: A tortoise tale

Desert critters and the Endangered Species Act



Opinion
Las Vegas Review-Journal


Native Las Vegan Harry Pappas was appointed to the Bureau of Land Management Citizen Advisory Council by then-Rep. Barbara Vucanovich. He later represented the State Rifle & Pistol Association on the Clark County Tortoise Advisory Council.

"They said the (desert) tortoise was threatened, so they had to fence off these huge areas and shut out all the cattle, which means no one is out there shooting the coyotes and the raven or trapping the lions anymore, so of course that wrecked the hunting," Mr. Pappas recalled, back in 2001. "They said anyone who found a tortoise had to turn it in" to Clark County authorities.

"So what happened? They got so overrun with tortoises being turned in that they told us they were going to have to start euthanizing them. I said, 'Hold on a minute, here. Euthanize them? Why don't you just drop them out in the desert?' They said, 'Oh no, they'll fight with the native tortoises that already live out there and they'll kill each other, because all these lands are already at saturation levels.' I said, 'Wait a minute, now: Which is it? How can they be "threatened," or "endangered" ... but now you tell us all these lands are at "saturation levels" for tortoises?' "

Cattle weren't the problem, Mr. Pappas has always insisted. In fact, cattlemen formerly reduced the populations of predators including the coyote and the raven, which benefited tortoise populations.

"But now they say the way to protect the tortoise is to fence off the land and not let the ranchers and the hunters in, when the biggest tortoise populations we ever had were in the '50s and '60s, when you had plenty of ranching, and plenty of hunting, and plenty of predator control," Mr. Pappas insists.

Needless to say, it's hard to qualify as a federal bureaucrat if you're not willing to keep repeating the same mistakes. It was also back in 2001 that Congress authorized Fort Irwin -- a prime site for desert combat training near Barstow in Southern California's western Mojave desert -- 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 finally began in March 2008.

But so far, at least 14 of the 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, many of which were fitted with radio transmitters.

Fifteen of 70 baby tortoises collected at the training center as part of the relocation program have also died of various causes, Army officials tell the Los Angeles Times.

The problem, they say, might be linked to a severe drought that killed off plants and triggered a crash in rodent populations. As a result, coyotes that normally thrive on kangaroo rats and rabbits are turning to 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 sharpshooters. The hunt, however, has been delayed by bureaucratic red tape.

The Center for Biological Diversity, the Tucson, Ariz.-based environmental group, meantime announces 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 big tortoise move.

William Boarman, an adjunct professor of biology at San Diego State University who's helping direct the translocation project, explains that after the Army decided to expand operations at Fort Irwin, "We were stuck with bad options: move the tortoises or leave them in place, which would have been much worse."

Said U.S. Geological Survey biologist Kristin Berry: "Coyotes didn't seem to be a problem when we started. The question in the back of all of our minds now is this: How could we have determined that this was going to happen?"

Oh, please.

As documented in Vernon Bostic's "Ecology of the Desert Tortoise in Relation to Cattle Grazing," the greatest death loss among Southern Nevada desert tortoises during the severe drought of 1981 occurred in the Crescent Valley Allotment, where cattle had been excluded from grazing.

"On the adjoining Christmas Tree Pass Allotment, which was grazed (by cattle) all year long, the tortoises were relatively unaffected by the severe drought. ... The reason is simple: Cows provide tortoises with both food and drink," wrote Mr. Bostic.

Cattle also help the tortoises by eating off the previous year's dried growth from grasses and other desert plants, clearing the way for new growth close enough to the ground to provide turtle fodder.

The solution? Move the Fort Irwin tortoises not onto parched habitat from which they will only start their long, lumbering walk home, but rather, onto well-maintained cattle grazing lands where local ranchers have improved the springs, putting in windmills, ponds and water tanks.

Slow, steady -- and under siege

Endangered tortoises airlifted from an Army base face other threats

By Louis Sahagun
Los Angeles Times

REFUGE: A translocated California desert tortoise in the shade of a shrub.
(John Vandewege / Los Angeles Times)

Video: Desert Tortoises Under Attack

BARSTOW -- 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."

Army's transfer of Mojave Desert tortoises tripped up by coyotes

By JENNIFER BOWLES
The Press-Enterprise

Coyotes have killed at least 11 desert tortoises recently moved to make way for Army tank training exercises north of Barstow.

The problem coyotes, thought to be attacking tortoises because the drought has left fewer rabbits in its wake, will be tracked and possibly killed by a federal agency to help protect the tortoises -- a species threatened with extinction

All together, 23 tortoises have been killed since the large-scale relocation of more than 700 reptiles began in March south of the National Training Center at Fort Irwin, said John Wagstaffe, an Army spokesman.

Some of the tortoises were already living in the relocation area.

Roy Averill-Murray, who is the desert tortoises recovery coordinator for the U.S. Fish and Wildlife Service, said three tortoises survived attacks. Two tortoises had one of their legs chewed off, and one of the reptiles required treatment after being found flipped over on its shell for three days in a row, Averill-Murray said.

Dr. Leonard Sigdestad at Loma Linda Animal Hospital in San Bernardino operated on two of the tortoises last week and amputated one maggot-infested leg from each of them. He released them back to the federal biologists who are monitoring the tortoises in the wild.

Kristin Berry, a research wildlife biologist with the U.S Geological Survey, took one of the tortoises to her Riverside home to care for it. She said it can barely walk but she hopes it can one day be returned to the wild.

Out by Fort Irwin, biologists have been tracking the relocated tortoises with transmitters glued to their shells on a daily basis and found the ones that died, Wagstaffe said.

The Army started moving the tortoises in late March from the southern boundary of the National Training Center at Fort Irwin as part of an $8.5 million effort to deal with the threatened species while expanding its training grounds into the land considered critical for the tortoises.

The move capped a 20-year battle between the military and environmentalists.

The U.S. Bureau of Land Management oversees much of the land selected for relocating the displaces tortoises. BLM officials a few days ago discussed strategies with other federal and state agencies on how to solve the coyote problem, said Doran Sanchez, acting associate manager of the agency's California desert district.

Attacks by coyotes on tortoises are rare, said Averill-Murray. He said that with the drought in the Mojave Desert over the past few years, coyotes outnumber rabbits, their typical food source,
"The coyotes are just desperate and the tortoises are a tough food item to eat with that big shell," he said. "Rabbits would be easier, but when there aren't many rabbits, then tortoises seem to be their next choice."

Berry, with the USGS, said short-lived animals like rabbits don't bounce back quickly from drought.

She said coyotes recently have killed tortoises in other study plots in California and Nevada but it is infrequent. This spring, she said, presented a good time to relocate the reptiles from Fort Irwin because of the abundance of wildflowers, their main food source.

"We hoped with the flush of wildflowers we might be seeing some ground squirrels and other rodents the coyotes could eat," she said. "You can take it into account but we can't control every aspect of nature, if any."

The wildlife service division of the U.S. Department of Agriculture, the same agency that plans to shoot ravens found preying on young tortoises in other parts of the Mojave Desert, will help the Army remove the coyotes in three, one-square-mile plots where many of the dead reptiles were found. The U.S. Fish and Wildlife Service concurred with the Army's plans to shoot or use traps and decoy dogs to capture the coyotes.

The job of decoy dogs "is to respond to coyotes calls and lure the coyote within shooting range," according to an April 15 letter to the Army by the U.S. Fish and Wildlife Service.

Averill-Murray said it will be up to the crews in the field to determine whether to shoot the coyotes. He said he was unsure if they could be relocated.

"The plan is just to keep this as targeted and as limited as possible to alleviate the pressure. It's not widespread," he said. He added that there's no evidence of major preying throughout the habitat where the tortoises were moved.

Two environmental groups have threatened to sue the Army over the large-scale relocation of the tortoises, and they plan to go ahead with the lawsuit to ensure the new habitat is managed actively, said Ileene Anderson, a biologist with the Center for Biological Diversity.

Anderson agreed with Averill-Murray that the drought has caused an imbalance in the ecosystem. But she said that's no excuse for putting the tortoises in harm's way.

"While we're devastated, we're not shocked this is happening," she said. "You're putting these animals out there and if they're the only thing moving, they're going to be a target for predators."

Wagstaffe said the move was done to the best of the Army's ability with the help of federal and state biologists, and the tortoises will continue to be closely monitored.

"Part of the beauty of doing a detailed study is we're going to learn a lot of stuff," he said. "And we'll find some things that we did very well and some that didn't go well."

Plan calls for killing ravens to save desert tortoise

By JENNIFER BOWLES
The Press-Enterprise

Ravens caught preying on desert tortoises will be killed under a plan announced Wednesday by federal wildlife officials seeking to protect the reptiles threatened with extinction.

The program will start in spring 2009 throughout the California desert, including Riverside and San Bernardino counties, where the number of ravens increased in some areas by more than 700 percent between 1969 and 2004.

The U.S. Fish and Wildlife Service considered comments by animal advocacy groups to use only non-lethal methods, but that would take too long to have an effect, said Judy Hohman, a biologist with the U.S. Fish and Wildlife Service.

Under the plan, federal wildlife officials will kill only ravens that appear to be preying on the threatened desert tortoises.

"We need to stop the decline of the desert tortoise population as soon as possible," Hohman said.

She said the plan incorporates non-lethal means, including efforts to educate the public in the Coachella Valley and other desert towns to place trash in covered garbage bins and not to over-irrigate lawns so that pools of water can be used by ravens for drinking.

Monica Engebretson, senior program associate with Born Free USA united with Animal Protection Institute, based in Sacramento, said she hoped the program would have included methods to prevent raven eggs from hatching and efforts to pass ordinances that would fine residents for not properly taking care of their garbage or lawns so that the effort is taken seriously.

The wildlife service crafted the plan with the National Park Service, the U.S. Bureau of Land Management and military bases in the desert.

Under the plan, a two-person crew from the U.S. Department of Agriculture's wildlife service will scour parts of the desert when tortoises are most active, from about early March through early June, Hohman said.

They will kill only ravens that appear to be preying on tortoises by shooting them, poisoning them or trapping and then euthanizing them. The poison that will be used is non-lethal to most other birds and wildlife, Hohman said. It will be injected into a hard-boiled egg and hoisted on a pole so it will be out of reach of other wildlife.

If that approach is unsuccessful, the crew will target all ravens in wildlife management areas and land considered critical to the tortoise's survival.

The program calls for killing a maximum of 200 ravens each year and will cost $200,000 annually, Hohman said.

Wildlife service accepts comments on raven assessment

Desert Dispatch [Barstow, CA]

The U.S. Fish and Wildlife Service has released a draft environmental assessment suggesting ways to reduce raven predation on the desert tortoise and other animals found in the deserts of Southern California.

Raven populations increased more than 700 percent in some areas of the California desert between 1969 and 2004, according to a Fish and Wildlife Service press release.

Alternatives for raven management include lethal and non-lethal techniques. To view the assessment online, go to www.fws.gov/ventura. Copies are also available at public libraries in the desert or by calling (805) 644-1766.

The Fish and Wildlife Service will accept public comments until May 7. Written comments should be submitted to U.S. Fish and Wildlife Service Raven Management Environmental Assessment, c/o Judy Hohman, Ventura Fish and Wildlife Office, 2493 Portola Road, Suite B, Ventura, CA 93003.

Comments can also be e-mailed to FW8draftravenea@fws.gov with "Raven Management" in the subject line.