Trail of the week: Lower Tubbs Island in San Pablo Bay

Part of the San Pablo Bay National Wildlife Refuge, this 8-mile trail between the Petaluma and Napa rivers gives birdwatchers a smorgasbord of shorebirds to gawk at.|

THE PRESS DEMOCRAT

March 30, 2016

San Pablo Bay National Wildlife Refuge

Lower Tubbs Island

Hiking distance: 5.5–8 miles round trip

Hiking time: 3–5 hours

Configuration: lollipop

Elevation gain: level

Difficulty: moderate

Exposure: exposed coastal marshland

Dogs: not allowed past picnic area

Maps: U.S.G.S. Sears Point and Petaluma Point

San Pablo Bay National Wildlife Refuge lies along San Pablo Bay at the northern reaches of San Francisco Bay. The wildlife refuge encompasses 13,000 acres between the mouth of the Petaluma River and Mare Island by Vallejo, including tidal wetlands, mud flats, salt marshes, and open water. Numerous water-ways drain through the surrounding terrain, including the Napa River, Petaluma River, Sonoma Creek, Tolay Creek, and many sloughs. The water-ways are interspersed with grasslands, oak woodlands, and agricultural fields. Lower Tubbs Island, near Tolay Creek, is the most accessible portion of the national wildlife refuge, luring bird watchers, wildlife photographers, and hikers. Lower Tubbs Island Bird Sanctuary is a 332-acre preserve within the refuge. It is a sanctuary for migrating birds, waterfowl, and shorebirds.

This trail follows a dirt levee 2.75 miles to the bird sanctuary on Lower Tubbs Island, then continues another 1.5 miles to Midshipman Point at the tip of the open waters. The terrain is flat, exposed, and windswept with wide open vistas.

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TO THE TRAILHEAD

5202 Sears Point Road • Sonoma

38.153294, -122.436086

From downtown Sonoma, drive 8 miles south on Highway 121 (the Carneros Highway) to a T-junction with Highway 37 (Sears Point Road). Turn left and head east on Highway 37. Drive 0.7 miles, crossing over Tolay Creek and skirting the lagoon, to the first right turn. Turn right and park on the right at the posted trailhead.

THE HIKE

Pass the trailhead gate and map panel on the dirt road. Follow the levee of Tolay Creek south along the edge of the wetlands and agricultural fields. At 0.4 miles curve left, passing a picnic area with an information map on the left. (Dogs are not allowed past the picnic area.) Continue southeast and bend right, with views of Mount Tamalpais and Mount Diablo in the distance. A parallel path follows the top of the levee on the right, overlooking the Tolay Creek Lagoon. At 1.6 miles, veer left and pass a metal pumping station on the left. Continue southeast to a trail split at 2.3 miles, located by an information kiosk, the viewing area, and the entrance into the Lower Tubbs Island Bird Sanctuary.

Begin the loop to the right between Lower Tolay Lagoon and Lower Tubbs Island, surrounded by tidal sloughs and salt marshes. Pass a group of red barns on the right, and curve left to the mouth of Tolay Creek. Follow the edge of San Pablo Bay on the levee road, where there is a view of Midshipman Point (the obvious promontory) and the mouth of the Petaluma River. At the east end of Lower Tubbs Island is a road split. Stay to the left along the Tubbs Island setback and complete the loop. Return to the right.

Source: “Day Hikes Around Sonoma County, 2nd Edition” by Robert Stone (Day Hike Books, 2016)

Everyone should visit Lower Tubbs Island at least once, if for no other reason than to say you’ve seen it. Without a dedicated trail such as this to follow, it’s hard to get the same kind of up close look at the shoreline of San Pablo Bay or the camouflaged sloughs and tidal marshes that emanate north.

Those of us who drive past Sears Point along busy Highway 37 also miss the long view that puts Sonoma’s rolling hills and farmers’ fields into geological perspective and gives birdwatchers a smorgasbord of shorebirds to gawk at.

Whether you will want to visit often is another story. The 8-mile round-trip requires a serious commitment of time and effort before you reach the bay, 2.75 miles south of the parking area. The return trip seems even longer because of the flat, unshaded dirt trail that at times disappears beneath waist-high grasses and at other times is so filled with muddy tire ruts that it is difficult to navigate.

The payoff for making what can at times feel like a very long slog is the 2.5-mile loop that follows the waterline to Midshipman Point and then circles north around the marshlands that form the Lower Tubbs Island Bird Sanctuary. Reports of an impassable section kept us from completing the loop.

The island is part of the 13,000-acre San Pablo Bay National Wildlife Refuge that stretches between the Petaluma and Napa rivers. Historically, it was used as a club for duck hunters, protected by levees that could be opened with the tides to release salt water into the sloughs.

In 1969, it was purchased by the Nature Conservancy, and in 1978, it was turned over to the U.S. Fish and Wildlife Service. Once the levees were breached on Lower Tubbs Island, the natural marshes returned.

On a recent Sunday, we amused ourselves along the trail to the bay by watching a farmer plow his field to the east, scaling the plant-covered berm that separates the trail from Tolay Creek and identifying objects we found in the dirt, most of them man-made. We found bent rebar, rock-sized pieces of blue-painted cement, shards of ceramic pipe, lengths of PVC pipe and even a few shell casings, although the entire National Wildlife Refuge is off-limits to hunters. The highlight of our trek was an old pumping station at about 1.5 miles.

We also spotted egrets, red-tailed blackbirds, a hawk that appeared to be nesting in nearby weeds, a flock of sandpipers knee deep in the surf and, unfortunately, a few hungry mosquitoes.

Next time we will bring our bikes, hit the trail early in the day and pack binoculars so we can spend more time focused on the stars of this show.