Endangered Rats Trapped for Relocation Study

Bearing small metal traps baited with seed-and-peanut-butter balls, scientists hired by the Metropolitan Water District fanned out across a dusty valley near here Friday in search of an elusive prey--200 endangered Stephens’ kangaroo rats.

Normally, trapping or otherwise disturbing the tiny rodents--which are on the nation’s list of endangered species--would invite a hefty fine and possibly a prison term.

But Friday’s operation is part of a federally sanctioned study designed to determine whether the animal can be safely scooped up and moved to a new habitat.

The answer to that question is crucial to the MWD, which wants to build a series of water supply projects on Riverside County land now occupied by colonies of kangaroo rats. Unless it demonstrates that the rodent can survive relocation, the Southland’s giant water wholesaler will have trouble developing its property because of restrictions imposed by the federal Endangered Species Act.

“What we hope to accomplish here is prove that the kangaroo rat can be successfully relocated from one place to another,” said Robbie Soltz, environmental affairs manager for the MWD. “By successfully, we mean that the animals will continue to thrive and reproduce . . . in their new home.”

MWD projects at stake in Riverside County include a new reservoir, new pipelines and new and expanded treatment plants. The facilities are part of a $4.4-billion water storage and distribution system expansion the district plans to carry out over the next 30 years.

A nocturnal, burrow-dwelling rodent that hops kangaroo-style on powerful hind legs, the tan-and-white rat once occupied 300,000 acres in Riverside, San Bernardino and northern San Diego counties. Habitat losses to agriculture and urban development have drastically thinned the rat populations, however, and today the species lives on only 22,000 acres of flat, barren land in western Riverside County.

In 1988, the rodent--which resembles a chipmunk more than a rat--was designated an endangered species by the federal government.

On Friday, a Las Vegas consultant hired to conduct the MWD’s $500,000 relocation project began placing the rectangular traps near 200 rat burrows next to the Double Butte Sanitary Landfill outside Winchester in western Riverside County.

Biologist Michael O’Farrell said the trapped rats will be taken to the San Diego Zoo for up to three months, then released on MWD land deemed suitable for them elsewhere in Riverside County. The transplants will be monitored for a year.

“The first thing we want to see is where they go,” O’Farrell said, noting that some of the rodents might “make a beeline” for home. If that occurs, the biologist said he will be able to recapture his subjects, which will be outfitted with tiny, battery-powered radio transmitter collars.