Bald Mountain Trail and Mt Umunhum Trail in Sierra Azul Open Space Preserve (Spring):
Birds and Wide Vistas
by Edward Rooks
This spring trip south of San José gives great vistas of the South Bay and views as far away as San Francisco and Mt Diablo. Butterflies and bees distract as you try to spot the calling California Thrashers, Wrentits and Blue-gray Gnatcatchers. Above, ravens and vultures are joined by hawks and swallows. Trails are alive with wildflowers, insects, and birds and if you're lucky, a Merriam Chipmunk or Western Whiptail among the manzanita.
Trip Covers: May - June
Key Birds: California Quail, Band-tailed Pigeon, Anna’s Hummingbird, Blue-gray Gnatcatcher, Wrentit, California Scrub-Jay, California Thrasher, California Towhee, Spotted Towhee, Purple Martin, Black-throated Gray Warbler
How to Bird
Sierra Azul Open Space Preserve contains 17,000 acres of wilderness in the Santa Cruz Mountains in South San Jose and is managed by the Midpeninsula Regional Open Space District. The name Sierra Azul means "Blue Mountains” in Spanish. The park includes three mountain peaks: Mount Umunhum at 3,486 feet, Mount Thayer at 3,478 feet and El Sombroso at 2,999 feet. Sierra Azul OSP trails connect Mt Umunhum with Hicks Road and run all the way to Lexington Reservoir in Los Gatos. The preserve protects the upper watersheds of the Guadalupe River and Los Gatos Creek.
View of Mount Umunhum from the Bald Mountain Trail. Edward Rooks
This guide covers the short, flat and wide Bald Mountain Trail, the almost 4-mile busy single-track Mt Umunhum Trail that connects the Bald Mountain parking lot to the summit, and a short loop trail at the summit. The small Bald Mountain parking lot fills up very early on the weekends, so plan to arrive before 8:30 am. Most of the people will be hiking the Mt Umunhum Trail; the Bald Mountain Trail will be quiet. The parking lot at the summit is large so if you choose to visit that area of the park, parking will not be a problem. The summit observation deck can get busy with people at times.
Mount Umunhum (Um-un-um) means “resting place of the hummingbirds” in Ohlone. Anna's Hummingbirds on Cobwebby Thistle by Edward Rooks
Bald Mountain Trail: Bald Mountain Trail is an almost level 0.8 mile one-way dirt road that rises to the scenic grassy knoll at the Bald Mountain summit (2,387 feet). Most of the trail faces south, so the vegetation is tolerant of constant exposure to the sun. The first half of the trail cuts through chaparral, the dominant shrub in the area, sometimes accompanied by white-flowering chamise. Shrubs and trees rise out of the chaparral, including Birchleaf Mountain Mahogany, Buckbrush, and Leather Oak with Sycamore and Bay trees in some sheltered valleys.
Wrentit by Edward Rooks
As soon as you step out of the car, you will start to hear a variety of bird calls from the chaparral. Listen for California Quail, Northern Flicker, California Scrub-Jay, Wrentit, California Thrasher and Spotted Towhee. At the trailhead you might spot the Western Whiptail running on the ground hunting for insects and spiders between the plants and shrubs. This colorful 12-inch long snake-like lizard has black and golden brown stripes, spots and swirls reminiscent of tigers’ stripes.
The Western Whiptail is wary of predators, so activity will scare them, but the sedate movements of a bird watcher give you a chance of spotting them at your feet. Edward Rooks
As you continue along this first half of the trail, take it slow and scan the trees and shrubs. California Thrashers often sing from the tops of bare branches while the Blue-gray Gnatcatchers will be flitting around in the Leather Oaks.
Blue-gray Gnatcatcher on flowering Buckbrush by Edward Rooks
Blue-gray Gnatcatchers have high pitched calls that sound like a chattering of buzzes and squeaks, but if you get lucky and if you listen carefully you can occasionally hear soft, high pitched samples of other birds' voices, like scrub jays, nuthatches and warblers. I heard a gnatcatcher once mimic a Red-tailed Hawk while it was looking up at the sky. I looked up and saw a Red-tailed Hawk flying overhead. People say the mimicry is to impress their mates, but I now wonder if there is more to it than that.
California Thrasher by Edward Rooks
The second half of this short trail passes stands of manzanita and live oaks, ending at the open grassy knoll at the Bald Mountain summit with sweeping views of San Jose to the north. To the east you look down on Almaden Reservoir, New Almaden and Almaden Quicksilver County Park. The southern slope offers impressive views of the slopes of the Santa Cruz Mountains sweeping down into Herbert Creek 1,500 feet below.
Grassy knoll at the Bald Mountain summit. Edward Rooks
This half of the trail offers a mix of vegetation including oaks, manzanita, and chaparral alongside open grassy areas. The diverse habitat makes it more likely that you see a greater diversity of birds. In the trees you are more likely to find Ash-throated Flycatcher, Bewick’s Wren, Bushtit, Northern Flicker, Hutton’s Vireo, Oak Titmouse, Orange-crowned Warbler, Blue-gray Gnatcatcher, and occasionally Black-throated Gray Warbler, Hermit Warbler, Wilson’s Warbler and Black-headed Grosbeak. In the more open areas you might find Western Meadowlark and Savannah Sparrow hiding and foraging among the grasses and wildflowers, while Dark-eyed Juncos, Spotted Towhee, Lesser Goldfinch, Purple Finch and Lazuli Bunting can be seen and heard among the shrubs and the trees.
Did you get distracted by all the wildflowers along this trail? Not only are the flowers beautiful, but also the wildlife that feeds on them such as the Yellow-faced Bumblebee or the Mormom Metalmark. (To read more about California’s native bees, read this blog post from the UC Davis Arboretum.) It is vital that we conserve even small habitat zones like Mt Umunhum.
Yellow-faced Bumble Bee on Lindley's Blazingstar. Edward Rooks
Mormon Metalmark on Naked Buckwheat flowers. Buckwheat is the Metalmark’s larval host plant and its primary nectar source. Edward Rooks
Mount Umunhum Trail: Starting from the Bald Mountain Trail parking lot, you can also bird the Mount Umunhum Trail which is a single-track, 3.7 mile one-way heavily trafficked trail to the peak of Mt Umunhum (elevation gain of 1,187 ft.). The trail is used for hiking, running, and mountain biking. The first 1.5 miles of the trail is level to the Guadalupe Creek Overlook. Trail access is across the street.
Mt Umunhum Trail: Manzanita dominant chaparral studded with Gray and Knobcone Pine can be found on the sunny exposed ridges while California Bay and Leather Oak woods predominate the parts of the trail that get more mountain shade. Edward Rooks
The greatest diversity of birds is found at the edge of the woods and in the chaparral, but while you are in the shaded woods keep an ear and eye out for Steller’s Jays, Thrushes, Dark-eyed Juncos, Chestnut-backed Chickadees, Pacific-slope Flycatcher, Hutton’s Vireos and Band-tailed Pigeons. Listen for the Black-throated Gray Warblers singing from the tree tops and the Orange-crowned Warblers trilling from the understory.
As you leave the relatively quiet woods and enter the chaparral areas, the sky opens up and you may see Turkey Vulture, Red-tailed Hawk and Cooper’s Hawk above you. Start listening as well. Bird watchers depend on their hearing to find most birds. The dominant bird voices of the chaparral include the loud squawks of California Scrub-Jay, the complex songs of California Thrashers, the dribble of Wrentits, the buzzing of Blue-gray Gnatcatchers, the loud melody of a Bewick’s Wren and the flute-like warbling song of a Purple Finch. Non-singing Spotted Towhee, California Towhee and California Quail will be rustling about in the leaf litter and branches nearby. Many of these birds are skulkers and hard to spot in the tangle of chaparral, but just stand still and listen. The birds will soon adapt to your presence and expose themselves.
California Quail by Edward Rooks
The cute and entertaining Merriam’s Chipmunks are active during the day and often spotted along these trails. Look for them near the ground, wherever you find piles of branches in the chaparral and among the manzanita. Their call is almost identical to the Northern Pygmy Owl’s call; it’s just a bit faster and higher in pitch. You can listen to their calls in the Earbirding blog post Pygmy-owl vs. Chipmunk.
Merriam's Chipmunk on Brittleleaf Manzanita. Chipmunks play an important role in the ecology of this park as they cache acorns and help disperse oak trees. Edward Rooks
The second half of the Mt Umunhum trail involves 8 long switchbacks, that make the steep ascent of 1200 feet easy to climb. The Steller’s Jays inhabit the mixed woods, along with sightings of Band-tailed Pigeon, California Scrub-Jay, Hutton’s Vireo and Purple Finch. Turkey Vultures, Common Ravens, White-throated Swifts and Violet-green Swallows frequently soar above the ridges and peaks of where people are drawn to see the panoramic views from the 3,486 feet high peak at Mount Umunhum.
Band-tailed Pigeon by Edward Rooks
The Summit: You can reach the summit by hiking the entire Mt Umunhum Trail or you can drive. To drive, start from the Bald Mountain Trailhead parking and continue 5.4 miles up Mt Umunhum Road. Turn left into the parking area (parking #2 on map). This parking lot is not all the way to the summit. You’ll need to take the short 0.2 mile loop trail to the peak that involves climbing several flights of stairs. Once at the summit, you’ll be rewarded with fantastic views from the observation deck and you can check out the historic radar tower.
Observation Deck and Radar Tower by Edward Rooks
The eight story box-shaped concrete radar tower on the peak is a local landmark visible from most of San Jose. That tower housed a radar dish operated by the US Air Force from 1957-1980. The radar tower was one of a system of 23 similar radar stations in California and one of hundreds across the country that fed radar signals into the Semi-Automatic Ground Environment (SAGE) defense system. The peak offers splendid vistas of San Jose and the South Bay. On clear days, you can see San Francisco and Oakland and as far as Mount Diablo and Mount Tamalpais.
In May and June look for Purple Martin, which are sometimes spotted here. Also watch for Turkey Vulture, Red-tailed Hawk, California Quail, Band-tailed Pigeon, Anna’s Hummingbird, Violet-green Swallow, White-throated Swift, Common Raven (omnipresent at the peak), Wrentit, California Scrub-Jay and California Thrasher.
Western Tiger Swallowtail patrol the summit for potential mates and perform spiraling courtship flights when they contact each other. Edward Rooks
Purple Martin, the largest swallow in North America. Brooke Miller
Species Lists of Bald Mountain and Mt Umunhum Trails
Ready for More? Another nearby trail to try is the Woods Trail starting from the Jacques Ridge parking area at the intersection of Hicks Rd and Mt Umunhum Road. The first two miles of this trail will take you through oak woodland, chaparral scrub and scattered conifers to Guadalupe Creek. Alternatively, you can bird the Wood Road Trail in Almaden Quicksilver County Park. The parking area for this bird walk is across the street from the Jacques Ridge Parking area.
Interactive Map
Directions
Via Camden Ave: From CA-85 in San Jose, exit Camden Ave south. Continue south for approximately 1.7 miles. Turn right onto Hicks Road and continue for 6.3 miles. At the stop sign, turn right onto Mt. Umunhum Road. Continue up the hill for 1.4 miles. Turn left into the parking lot. Via Almaden Expressway: From Highway 85, drive south on Almaden Expressway for 4.2 miles to Almaden Rd. Turn Right on Almaden Rd and drive for 3 miles, through the town of New Almaden, to Alamitos Rd. Keep straight and drive for 1.6 miles, past Almaden Reservoir to Hicks Rd. Turn Right on Hicks Rd and drive uphill for 1.7 miles to Mt Umunhum Rd. Turn Left on Mt Umunhum Rd. Drive up Mt Umunhum for 1.7 Miles to the Bald Mountain Trail Parking Lot.
Note that Mt. Umunhum Road is steep, narrow, and winding with blind curves but the road is in good condition and the views are great. Road cyclists enjoy this road. Bald Mountain parking lot, Latitude/Longitude: 37.159546, -121.875520
To reach the peak, continue up the hill for another 5.4 miles.
Parking: Paved parking lot
Fees: None
Public Transportation: None
Hours: Open from one-half hour before official sunrise until one-half hour after official sunset
Facilities: Wheelchair accessible pit-toilet in the Bald Mountain Trail Parking Lot. Accessible pit-toilet at the Mount Umunhum parking lot. Shaded picnic tables available at the peak. Limited or no cell phone service.
Heads-up! The area has limited to no cell phone service. To print or download this guide before you go, select the text you want (don’t include the banner photo), then print to PDF, or use a free service such as printfriendly.com, which lets you shrink or remove photos.
Trip Mileage: 1.6 miles round-trip for the Bald Mountain Trail. Up to 7.4 miles for the Mount Umunhum Trail but easy to shorten. The short trail starting from the highest parking lot to the radar tower has many flights of stairs but there is an additional accessible parking lot with drop-off zone if you need to skip the stairs.
Trail Conditions: The Bald Mountain Trail is a flat dirt fire road with little shade and few people. The more popular 3.7 mile one-way Mt. Umunhum Trail is a busy single track dirt trail with 1,700 ft elevation gain. Weather warning: If there is wind, fog, or any weather in the area, Mt Umunhum is exposed and will probably be impacted.
Accessibility: The Bald Mountain Trail is flat and wheelchair accessible. Accessible parking, restrooms, shade shelters, picnic tables and pathways are located at the Mount Umunhum Summit. At the main visitor parking area, visitors can use the accessible parking and restrooms. At the Summit turnaround area (parking area 3 on map), there are three accessible parking spaces and a passenger drop off area. Visitors can enjoy the accessible pathway to the west summit that leads to the ceremonial circle, the east summit view point, the summit shelter, and the interpretive displays.
Bikes: Bikes are allowed on the Bald Mountain Trail and the Mount Umunhum Trail but not recommended for this trip.
Dogs: Dogs are NOT allowed on the trail, summit, parking lots, or roads in the Mount Umunhum area (includes dogs in cars).
More Information
Sierra Azul Preserve Website
Mount Umunhum Website (an audio tour is available)
Sierra Azul Trail Map
eBird hotspot: Bald Mountain Trail, Mt Umunhum Trail, Mt Umunhum
Read “Beyond the honey bee: Learn more about California native bees” from the UC Davis Arboretum and Public Garden blog.
More Resources
For more trips like this one, visit Self-Guided Field Trips.
Visit the SCVAS Birding Resources page for more information on where to bird, our birding community, bird identification resources and more.
Read “What to Look for Now” by SCVAS Executive Director Matthew Dodder.
Banner Photo Credit: Mount Umunhum by Edward Rooks
Last Updated: 5/20/2022
Enjoyed this Trip?
Support the work of Santa Clara Valley Audubon Society and become a member. To contact the trip writer with comments, questions or location updates, please email fieldtrips@scvas.org. You can also post in the comment section below. (If you’d like to post anonymously, type your comment, select “Post Comment”, then simply provide a name, like “Guest”, and select “Comment as Guest”.)