Rats Help Ferret Out Data on Urban Sprawl : Conservation: A researcher has spent the summer studying rodents and other small mammals to see how development affects wildlife.

Ray Sauvajot took the wood rat out of the metal box trap and grasped it by the scruff of the neck. With a green Magic Marker, he streaked the belly fur before releasing the creature into the brush.

During the last two months, Sauvajot has dyed enough chaparral rodents to start a punk fashion craze. But that is not why he and his colleagues have spent the summer on the hot, brushy slopes of the Santa Monica Mountains.

A research ecologist and doctoral candidate at UC Davis, Sauvajot, 25, is heading a multi-year study exploring questions that are central to wildlife conservation efforts in the Santa Monicas, where rampant development exists alongside a network of protected mountain parks.

How does development on the urban fringe affect neighboring wildlife preserves? Does such urban encroachment reduce wildlife diversity? Could it lead to extinction of sensitive species, such as mountain lions?

The study, by Sauvajot and his research collaborator, Marybeth Buechner, relies on an intensive program of trapping small mammals and observing birds throughout the mountain range. The small animals are considered good indicators of environmental change and are prey for larger animals that are more difficult to study.

Although final results are not expected for at least a couple of years, one preliminary finding seems encouraging. Within peninsulas of habitat that jut into developed lands, wildlife diversity seems comparable to that in more isolated, interior areas of the mountains. Sauvajot stressed that this is more an impression than a firm result.

But on a recent morning, as Sauvajot and his volunteer assistants, 21-year-old UC Davis undergraduates Sara Kelly and Andor Czigeledi, checked their traps, one amusing conclusion seemed well-established. Judging by their captive rodents and their rainbow coiffures, it appeared that hunger conquers fear.

Consider the desert wood rat with the wild green painted streak, which urinated and squirmed to avoid being handled. The terrified creature had been through it all before. Magic Marker streaks established that, for three straight days, the plump rodent had been unable to resist the siren’s song of peanuts and sunflower seeds.

“This is the third time we’ve caught this individual,” Czigeledi said. Being trapped “apparently . . . is not that stressful.”

The study is to be Sauvajot’s doctoral dissertation and may appear someday in scientific journals, perhaps evoking images of white lab coats and climate-controlled surroundings. The reality--a punishing routine of grunt work--is far different.

Every day since July 1, without a break for weekends or holidays, Sauvajot and his colleagues have rolled out of their sleeping bags at nearby Malibu Creek State Park a little after sunrise for the start of a long day’s work. From there, they have driven to trail heads near the Mulholland crest, for the first of two daily visits to their trap lines.

In the morning, they hike to two trapping areas, checking 100 traps. They release the captured animals after logging pertinent data, such as sex, physical measurements and whether the animals are recaptures.

The markers used to tag the animals have nontoxic ink that fades quickly, the researchers said. It is applied only to the animals’ undersides so they wouldn’t be more conspicuous to predators.

During their morning rounds, the researchers also made a record of birds in the trapping areas, identifying them by bird calls and sight.

To ensure that none of their captives died inside the metal traps during the heat of the day, the researchers closed all the traps after checking them in the morning. Then they headed back to camp to rest until late afternoon, when they returned to set the traps.

Throughout the summer two lines of 50 traps were moved from one spot to another every five days. By the middle of last week, the group had finished monitoring its 15th and 16th trapping areas, bringing the current phase of the study to an end.

Sauvajot now heads back to Davis to regroup and look for financial support to continue his work. Despite the help of volunteers and parks agencies, he said he has barely scraped by.

He and his assistants have camped free this summer at Malibu Creek, courtesy of the state Department of Parks and Recreation, which also operates Topanga State Park, where some of the trapping has been done. And the National Park Service, which administers the Santa Monica Mountains National Recreation Area, lent Sauvajot the box traps and a four-wheel-drive vehicle to navigate the bone-jarring surface on the unpaved portion of Mulholland.

Wildlife and Development Researchers are observing birds and using live traps to capture rodents in the Santa Monica Mountains as part of a study on how private development affects wildlife in nearby protected parklands.