Discover Riverside County's Santa Rosa Plateau Ecological Reserve at its springtime best.

The Los Santos-Trans Preserve loop hike on the Santa Rosa Plateau near Temecula traverses open meadows, grassy hillsides, and shady glens presided over by oversized specimens of Engelmann oaks. You'll enjoy superb views throughout, plus excellent opportunities for bird and wildlife watching. Note that in deference to the local wildlife, pets are not allowed on the trail.

To get there, exit Interstate 15 at Clinton Keith Road in Murrieta, north a few miles from Temecula. Drive south on Clinton Keith Road. Note the turnoff for the Santa Rosa Plateau Ecological Reserve visitor center, five miles from I-15. Continue (without making any turns but following the curves of the roadway) to the Hidden Valley trailhead on the left, 1.5 miles from the visitor center.

From the trailhead walk south, uphill, using the wide, unpaved Hidden Valley Road, which is closed to car traffic. After only 0.2 mile, make a right on the narrow Los Santos Trail. This delighfully primitive path crookedly ascends some bald hillsides, gains a ridgetop, and passes a resting bench just south of a 2084-foot knoll. From this overlook point, the bulk of the reserve's sensuously rolling terrain lies in full view. Perhaps this is the ideal spot to break out your high-powered binoculars to scan for deer in the meadows below and to track raptors gliding in the sky above.

Beyond the overlook, the Los Santos Trail drops into an upper tributary of Cole Creek and bends left to follow the tributary's tiny (and usually dry) brook. After just 0.1 mile, the path ahead assumes the proportions of a dirt road and continues southeast to join Hidden Valley Road. Don't miss the sign on the right, which directs you onto the sharply ascending, again delightfully primitive, south branch of the Los Santos Trail.

You climb to the rim of an oak-dotted plateau, a northward extension of the nearby Mesa de Colorado. Underfoot, there are small outcrops of basalt, a dark-colored volcanic rock. Basalt underlies the entire plateau, and its tough, erosion-resistant character is responsible for the plateau's elevated position. The softer, marine sedimentary rocks associated with the terrain behind you have eroded to form all those sensuously rolling hills and valleys.

Los Santos Trail continues south, dipping into and out of a shady ravine, then enters Mesa de Colorado proper, where you arrive at a junction with the Vernal Pool Trail. You've now come 2.4 miles, exactly halfway around the loop.

Turn left on the Vernal Pool Trail, proceed 0.3 mile, and turn left on the Trans Preserve Trail. (Note that one of the largest vernal pools in California lies just ahead on the Vernal Pool Trail; don't miss it if you haven't seen it before.)

On the Trans Preserve Trail, you meander northeast, descend off the plateau rim by way of an oblique course down a gorgeously oak-draped hillside, and strike a near-level, northward course alongside Poppy Hill -- one of several good sites in the reserve for viewing California poppies. On ahead, you gently curve and descend along another Cole Creek tributary ravine, and (4.3 miles into the hike) you reach the Coyote Trail. Turn left and complete the remaining half mile to Hidden Valley Trailhead.

This article contains information about a publicly owned recreation or wilderness area. Trails and pathways are not necessarily marked. Conditions can change rapidly. Hikers should be properly equipped and have safety and navigational skills. The Reader and Jerry Schad assume no responsibility for any adverse experience.