Hunters Tracking These Predators Want Information, Not Trophies

Standing on the ridge of Castro Crest, with the flanks of the Santa Monica Mountains sweeping down and away, Mike Williams swings the antenna in a wide arc, panning the ravine below. Midway through the sweep, the beeps start.

“This isn’t where we’d expect to find him,” Williams said, making notes in a logbook. “This could be his home range, but it’s a little more likely he hasn’t established a home range yet. That could be what we are seeing.”

“He” is a young male gray fox, one of four gray foxes equipped with radio transmitters that are scurrying through the underbrush of the Santa Monica Mountains National Recreation Area above Malibu.

The beeps are steady, indicating an animal at rest, not unusual for a gray fox in the middle of the day. Williams, a National Park Service resource management specialist, uses a compass to draw a bearing on the animal.

Williams radios volunteer Gail Bramhall, who is out of sight on a knoll a mile away and equipped with a similar antenna. Bramhall also has a fix on the young fox. Using the two bearings, the animal’s position is noted. That he is outside his normal range is unusual but not surprising.

“Once you make a rule, it’s bound to be broken real fast,” said Williams, smiling. “Although our job is prediction, sometimes it’s hard to predict anything out here.”

For two years, the National Park Service has been monitoring the movements of a small group of bobcats, coyotes and gray foxes--the area’s most important predators--in a sliver of the Santa Monica Mountains. The animals are captured in padded leg traps, and radio transmitters are affixed to them before they are set free. Researchers then track the animals to see what they do, where they go and how they interact with each other.

Park service personnel hope that the Critical Habitat Study will help them better understand the habitat needs of the animals, which, in turn, will help them manage the land the animals call home.

There are no conclusions yet, and there may not be for some time, but researchers believe that the study is needed to determine the impact of encroaching development on 150,000 acres of wilderness bordered by one of the country’s largest urban centers.

“A lot of people don’t realize it, but the Santa Monica Mountains are an excellent wildlife habitat,” said park service forester Robert Plantrich, the project leader. “Unfortunately, thousands of acres are being developed every year. We’re losing important habitat for many species without really knowing what it is they need.”

For two years, Plantrich, Williams and a small cadre of volunteers have logged the food, water and space needs of about 30 animals in 10 square miles of Malibu Creek State Park, a rugged expanse of deep canyons, wind-swept crests and rolling savannas. The emerging picture has been informative, interesting and, at times, surprising.

It has also been frustrating. Canyon walls block transmissions. Interference can smother them. Even clear transmissions are no guarantee. On one occasion, puzzled researchers followed a signal into the Simi Hills far outside the study range, only to find that they were tracking an Andean condor tagged by U.S. Fish and Wildlife Service for another project.

Williams and Bramhall have spent the last six hours bumping along rutted fire roads, stopping at ridge tops to pan the skies with antennas, electronically groping for signals from the three bobcats, four gray foxes and seven coyotes they are monitoring. In the course of a six-hour day, they can usually locate all the animals. Today they have found one, the young gray fox that has apparently wandered outside his range.

Standing on the ridgeline of Castro Crest, notching the day’s sole find in his logbook, Williams shrugs.

“Those are just some of the things that go with the territory,” he said. “There are days when everything goes right, and there are days when nothing is easy. Like the animals you’re tracking, constant change is the name of the game.”

Nowhere is this change more evident than at civilization’s edge, a portion of the predator-study area bordering the Malibu Lake community. Homes around a man-made lake provide an opportune look at development’s effect on the predators under study, especially the coyote, which seems to be thriving right on man’s doorstep.

The behavior patterns of tagged coyotes living on the edge of Malibu Lake appear to be markedly different from their counterparts in more secluded areas. In remote areas, researchers found coyotes spreading over a wide range of habitats, foraging day and night for the small mammals, fruits and nuts that are their natural food supply.

However, coyotes living near the lake seldom stray far and rarely forage during daylight. Instead, the animals rest in the brush just outside the development during the day, then pad down into the neighborhoods at night. There they find a ready supply of food in the form of garbage and occasional pets, upsetting the natural predator-prey balance.

“We now see and hear many more coyotes adjacent to residential areas than in areas that are less populated,” said Plantrich, who sees increasing potential for problems as development continues to displace, then provide for, the opportunistic coyote.

“In urban areas,” he said, there eventually will be a larger population of coyotes exhibiting less fear of humans. “That’s where problems may arise.”

Development’s effect on the bobcat and gray fox is less obvious. Far more reclusive than the coyote, these animals usually keep to thick brush and avoid contact with humans.

But researchers have observed a surprising habitat separation between coyote and gray fox. Natural enemies--the larger coyote sometimes feeds on the gray fox--as coyotes become more numerous, they may drive the gray fox further afield. Bobcats, equally intolerant of humans, also disappear in areas adjacent to development.

According to Plantrich, portions of the Santa Monica Mountains Recreation Area--notably eastern areas in and around Los Angeles--already provide an example of just such displacement.

“When you isolate an area, make it a park and then build boundaries around it, ultimately all you have left is coyotes,” Plantrich said. “Any biologist will tell you that as you fragment your habitat into smaller and smaller pieces, species diversity will decline.”

For the moment, animals in the recreation area’s western sections, the study area included, appear to be diverse and thriving. Researchers say the fact that they captured about 30 animals in a two-square-mile area is a good sign. Even more surprising, researchers say, is that they trapped more bobcats than coyotes.

Although none of the three predators under study appears to be in any immediate danger, Plantrich said, encroaching development threatens park boundaries. Heavily traveled roads such as Las Virgenes and Kanan roads already bisect the park. Widening these roads and building others could partition the ranges the animals need to survive.

“We have to look at the parks that exist in the Santa Monica Mountains right now--Topanga, Malibu Creek State Park, Point Mugu--and find a way we can link these areas,” Plantrich said. “If they become island communities, they can’t be expected to support their current populations over the long term.”

The study is officially winding down; no more animals are being tagged. But park service personnel say they will continue to monitor the tagged animals until they have enough data to evaluate conditions. Results, dutifully logged in computers, are now being analyzed.

Hard data aside, researchers say the study has offered a glimpse of something more.

“I’ve seen some things in these animals that are positively uplifting,” Plantrich said. “Loyalty. Courage. Bonds that can last for life. We’ve got a unique opportunity here to preserve something quite special.”