Sierra Vista OSP (Fall/Winter)
by Chris Johnson
Sierra Vista OSP is in the eastern foothills of Santa Clara County. It is a good location to visit year-round, but especially in the winter when grassland loving sparrows and Ferruginous Hawk may be present. There are few crowds in the early morning and weekdays and the views are fantastic.
Key Birds: Golden Eagle, Ferruginous Hawk (Dec-Mar), Yellow-billed Magpie, Horned Lark, American Pipit
Trip Covers: Sept - March
How to Bird
It's best to start early in the morning, between 7 and 9 A.M., before the parking lot fills up and birds are scared away. Before hitting the trails, check out the parking lot and the area around the cattle corrals for bird activity such as Red-winged and Brewer’s Blackbirds as well as Brown-headed Cowbirds. There is often water dripping from a faucet and this can attract birds throughout the day.
The cattle corrals and view from the Sierra Vista parking lot. Photo by Laura Coatney
Walking along the road can also be productive as the fences serve as perches for sparrows, Yellow-billed Magpie, and other birds in the early morning. I've found Grasshopper Sparrow (Apr-Oct), Lark Sparrow and Horned Lark this way. The rocky area just south of the parking lot often has one of the resident Rock Wrens and there are Western Meadowlarks here as well.
Yellow-billed Magpie in flight. Photo by Chris Johnson
Next, I take the Aquila Loop Trail which is accessible across the road from the parking lot. This dirt-trail loop is a little over a mile and typically less crowded than the other trails and has scenic look-outs of the valley. Check for Rock Wren and Burrowing Owl around the rocky outcroppings at the start of the trail. There are usually Yellow-billed Magpies making noise down in the valley and they are often observed in large flocks.
Aquila Loop Trailhead. Photo by Laura Coatney.
The loop will take you through various grassland, scrub and oak habitats. While on your walk listen for the calls of White-breasted Nuthatch, Oak Titmouse, Acorn Woodpecker, Northern Flicker (fall/winter) and other oak specialists. American Pipit, Say’s Phoebe and Savannah Sparrow are also common in fall and winter months on this trail.
Picnic table along the Aquila Loop Trail. Photo by Laura Coatney
Horned Lark can be seen anywhere around this area, but check for them as you near the end of the loop trail as this is a common area for them to forage for insects and seeds. They tolerate people quite well and are often just off the trail in a large group. Listen for their tinkling high-pitched calls as they fly overhead.
In winter, check the skies for rare or uncommon wintering raptors such as Ferruginous Hawk, Prairie Falcon, and Merlin. Ferruginous Hawk has been reported four of the last six winters while Prairie Falcon has been observed three of the last six years. Look for the Ferruginous Hawk’s rusty colored wings (ferruginous means reddish-brown) and completely feathered legs that form a “V” in light morph individuals. Dark morphs will be mostly dark chocolate brown with light flight feathers, while all morphs have a large prominent head and wide gape. Golden Eagle, Burrowing Owl, Northern Harrier and other common raptors also become more numerous in the winter.
Ferruginous Hawk (light morph) by Chuq Von Rospach
Northern Harrier on a snag along the Aquila Loop Trail. Photo by Laura Coatney
Ready for More? On the same side of the road as the parking lot you can access the Kestrel Trail which takes you to the Sierra Vista Trail. The hiking is more difficult and slightly more popular among visitors, but it's a good place to look for Golden Eagles as they hunt ground squirrels. Before you descend, scan the skies for Golden Eagles and check the rocky outcrops for American Kestrels and Rock Wrens. As you enter the treeline there will be more water and springs, which means better chances to see more birds. Check any wet areas as they are likely to host Lincoln Sparrow, Hermit Thrush, and more.
Come back to Sierra Vista in spring for good opportunities to spot Western Kingbird, Grasshopper Sparrow and Bullock’s Oriole.
Interactive Map
Directions: From I-680 in San Jose, exit Berryessa Rd. Travel east towards the hills for a little over a mile. Turn left onto Piedmont Rd, then turn right onto Sierra Rd (be prepared for a curvy, uphill drive). The preserve parking lot is on your right in about 4 miles. Note that the parking lot is small and may fill up. There is no alternate parking area. Latitude/Longitude: 37.409140, -121.801635
Parking: Small parking lot
Fees: None
Public Transportation: None
Park Hours: 7 AM to 7 PM Hours vary with the season so check before you head out.
Facilities: No bathrooms or drinking water; consider using the facilities at the Penitencia Creek Park before heading up the hill. 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, then print to PDF or use a free service such as printfriendly.com.
Trip Mileage: 1.2 miles
Trail Conditions: The Aquila Loop Trail l is dry in the dry season and can be muddy in the wet season (bring boots if going after heavy rains). There are often cattle grazing in the area so watch where you step. There is one picnic table and two benches along the trail. The hiking is easy to moderately difficult.
Accessibility: While the trail is not very accessible, the parking lot has great views and has good birding. There are benches in the parking lot. The trail entrance has a barrier so it may be inaccessible for some.
Bikes: Bikes are allowed but not recommended for this trip.
Dogs: Allowed on 6ft leash
More Information
Sierra Vista Open Space Preserve Website
Sierra Vista Open Space Preserve Trail Map
PDF version for printing or downloading
eBird hotspot: Sierra Rd Summit
All About Birds: Ferruginous Hawk
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, birding identification resources, and more.
Read “What to Look for Now” by SCVAS Executive Director Matthew Dodder.
Banner Photo Credit: Horned Lark by Chris Johnson
Last Updated: 03/23/2022
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