The Army's National Training Center at Ft. Irwin on Friday suspended its effort to move California desert tortoises off prospective combat training grounds and onto nearby public lands because the animals are being hit hard by coyotes.
The first phase of the $8.7-million translocation effort began in March, when about 670 tortoises were airlifted by helicopter out of the southern portion of the desert base northeast of Barstow to new homes in drought-stricken western Mojave Desert areas.
Since then, at least 90 translocated and resident tortoises in those areas have died, most killed and eaten by coyotes, according to federal biologists monitoring the project.
"We shut it down because of the mortality rate," said John Wagstaff, spokesman for the base.
"It will remain on hold until the Army and U.S. Fish and Wildlife Service determine the reasons behind it."
Biologists theorize the problem may be connected to severe drought conditions, which have 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 tortoises for sustenance.
They also point out that translocated tortoises tend to wander, sometimes for miles, making them lumbering targets for hungry predators.
Gashes and tooth marks in the shell of one translocated tortoise discovered in April by federal biologists indicated that it had been ripped out of the front of its carapace.
Other threats include vehicle traffic and an infectious respiratory disease.
The disease was prevalent in the relocation area and now the newcomers are catching it.
In July, the Center for Biological Diversity, a Tucson-based environmental group, sued the Army, the U.S. Fish and Wildlife Service and the U.S. Bureau of Land Management, accusing them of violating the federal Endangered Species Act in their management of Gopherus agassizii.
In a prepared statement released on Friday, Ileene Anderson, a biologist with the center, said, "We predicted that the translocation of tortoises from Ft. Irwin's expansion would be disastrous and, unfortunately, we were proven right.
"This whole debacle needs to be significantly rethought," Anderson said.
"The loss of so many tortoises is certainly not helping this threatened population."
The 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 to unoccupied public lands.
"The Army cares very much about these tortoises," Wagstaff said.
"That's why we've devoted a lot of money and research to them over the past 20 years."