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◆Hayward Regional Shoreline ◆

COGSWELL MARSH

Length: Approximately 3.3 miles

Time: 2 to 3 hours

Rating: Easy

Regulations: EBRPD; no dogs.

Facilities: A small visitor center, open only on weekends, 10 A.M. to 5 P.M., with toilets, water, books, maps, exhibits, and information.

Directions: From Highway 92 eastbound at the east end of the San Mateo Bridge in Hayward, take the Clawiter Road/Eden Landing Road exit. At a four-way stop, turn left onto Clawiter Road, cross over the highway, and at the next four-way stop turn left onto Breakwater Ave. Almost immediately, Breakwater Ave. turns left, then veers right and heads west, parallel to Highway 92. Follow Breakwater Ave. to the Hayward Shoreline Interpretive Center, about 1 mile from Clawiter Road. Park on the right side of the road. The trailhead is behind the visitor center.

From Highway 92 westbound at the east end of the San Mateo Bridge in Hayward, take the Clawiter Road/Eden Landing Road exit, and from the four-way stop at the end of the exit ramp go directly across Clawiter Road onto Breakwater Ave., then follow the directions above.

Hayward Shoreline Interpretive Center, located on Breakwater Ave., just north of Highway 92. The Hayward shoreline is a good place to see shorebirds, ducks, geese, gulls, herons, and egrets. It is also home to the endangered salt marsh harvest mouse.

The Hayward Regional Shoreline is one of the best places in the East Bay to view shorebirds. The trails are easy and bring you close to the water. The birds are used to people and will generally stay put. This semi-loop route goes through a restored marsh—a great example of how nature, with a little help, can reclaim areas previously altered by human intervention. The area gets windy in the afternoon, especially during spring and summer.

From just behind the visitor center, operated by the Hayward Area Recreation and Park District, take a moment to look out over the system of marshes around you. To your left are the Oliver Ponds, remnants of a vast salt-harvesting industry that began during the mid-19th century in San Francisco Bay and still exists today in limited areas of the Bay. Four generations of the Oliver family farmed salt on the Hayward shoreline, and the Hayward Area Recreation and Park District (HARD) purchased the ponds from the Oliver estate in the mid-1990s. The area directly in front of you is the HARD Marsh, former salt ponds restored to tidal action in 1986. Beyond lies the fresh and brackish water Hayward Marsh, an EBRPD project created in 1988 to naturally cleanse and release into the Bay some one million gallons per day of secondary treated sewage discharge water. To your right is habitat managed for the endangered salt marsh harvest mouse.

Turn left and begin walking west on a wide, hard-packed dirt path; your route will be along the levees that crisscross this area. The 1-mile trail from the visitor center to the Bay honors Arthur Emmes, a prominent Castro Valley optometrist and member of the Hayward Area Shoreline Planning Agency’s citizen advisory committee, who championed acquisition and development of trails along the shoreline. After reaching the Bay, this trail joins EBRPD’s trail system, which continues north about 7 miles to the San Leandro Marina.

As you walk toward San Francisco Bay, following a slough on your left, scan the marsh to your right for shorebirds, a tribe that includes oystercatchers, avocets, stilts, plovers, willets, curlews, godwits, small sandpipers, dowitchers, and phalaropes. In just a few minutes you may see a fine assortment, including black-necked stilts, American avocets, long-billed curlews, marbled godwits, dowitchers, and sandpipers, along with other water-loving birds such as egrets, ducks, and gulls. In the grassland areas, watch for resident savannah sparrows and blacktail jackrabbits.

Once you reach the shoreline, in about 0.8 mile, the route turns north and runs along the water. From here you have terrific views, on a clear day, of San Francisco, Oakland, the Bay and San Mateo bridges, the Oakland and Berkeley hills, Mt. Diablo, and Mt. Tamalpais. If the tide is out, you will see shorebirds during most of the year, feeding on the mud flats at the edge of the Bay. Some species, such as American avocets and black-necked stilts, breed in the Bay Area, but many others fly north in May and June to breed in Canada, Alaska, and the Arctic, which accounts for their absence from our area during those months. But during the rest of the year, and especially in winter, San Francisco Bay hosts one of the largest concentrations of shorebirds in North America, sometimes more than one million strong. The Bay is also the most important stop on the Pacific Flyway, the aerial route between northern breeding grounds and wintering areas in southern California, Mexico, and Central and South America.

As you turn north, the route crosses another slough, whose water passes under a short bridge and makes several jogs on its way around the west edge of Hayward Marsh. Two of the most common marsh plants, pickleweed and cord grass, are evident here. Pickleweed, a low-growing plant with many stubby branches, thrives in the middle marsh, where it is moistened only briefly by the tide’s salty flow. Light green in spring and summer, pickleweed brightens marshes in the fall as it turns red and purple, but winter finds it dull brown. Cord grass, 1 to 4 feet tall and dark green, lives low in the marsh and is well adapted to twice-daily flooding by the tide. Cord grass, like other plants, is an air purifier, consuming carbon dioxide and carbon monoxide, and releasing oxygen into the atmosphere. The orange threads that you may see wound in the pickleweed is salt-marsh dodder, a parasitic plant.

After walking about a mile, you reach a junction with a path going right, which you will use later on your return. But for now, turn left and return to the shoreline at Johnson’s Landing, a cove with a small beach and breakwater. John Johnson began harvesting salt from San Francisco Bay by putting levees around natural pools in the marsh. This landing, like others along the shoreline, was built in the 1850s for boats that carried salt, waterfowl, agricultural products, and passengers to San Francisco.

As you turn north and continue walking along the water’s edge, a sweeping view of the Alameda County shoreline stretches before you all the way to Oakland. This part of the route is also a segment of the San Francisco Bay Trail, which uses existing trails and roadways owned and maintained by various public agencies and will some day encircle the Bay. More than half of the Bay Trail’s proposed 400-mile route has been completed. On your right is Cogswell Marsh, named in honor of Dr. Howard L. Cogswell, a well-known Bay Area shorebird biologist, educator, and member of EBRPD’s board of directors from 1971 to 1982. This large marsh consists of several former ponds restored to tidal action by an EBRPD levee-breaching project completed in 1980.

A birder checks area near Cogswell Marsh for shorebirds.

Soon you reach the first of two bridges that span breached levees in this section of the shoreline. Here is an excellent vantage point from which to study shorebirds feeding on the mud flats below. Time your arrival just after high tide, when the water begins to recede and more and more of the flats are being continuously exposed. Different shorebirds have evolved different strategies for feeding, from the avocet’s side-to-side swiping motion, to the dowitcher’s rapid, machine-like drilling. The largest North American shorebird, the long-billed curlew, probes deep in the mud for small clams using its long, down-curved bill. The bird will then rinse off its muddy prize before swallowing it whole.

After crossing the first bridge, continue north, with the Bay on your left and the salt marsh spreading out to your right. Soon the route turns right, away from the bay, and heads east. On your left is a large inlet, with the second bridge ahead. On a rising tide, shorebirds feeding in the shallows of this inlet are pushed toward shore, so this is another great vantage point for observing their antics. And because you are facing north as you look out across the inlet, the sun is behind you for most of the day, another plus when viewing birds. Across the Bay to the northwest, the light-colored buildings of San Francisco are thrown into relief by the dark background of Mt. Tamalpais.

At the second bridge, after you’ve had your fill of birding, turn right and begin your return trip along a dike with a slough and salt marsh to the left. (If you want a longer hike, cross the bridge and follow the route northeast, then west to Triangle Marsh and Hayward’s Landing.) Check the slough for ducks; especially pretty are ruddy ducks in bright plumage. After walking south for about 0.5 mile, turn right on a dike leading back to the bay. If the tide is coming in, especially just before sunset, you may see large flights of shorebirds coming to roost in Hayward Marsh, left. Soon you rejoin the original route near Johnson’s Landing; turn left here and retrace your route to the visitor center.