Birding along the San Francisco Bay Trail at Redwood Shores

My hike along the Redwood Shores segment of the San Francisco Bay Trail turned out to be a great opportunity for observing shorebirds and waterfowl. I thought I might see some shorebirds, but I really didn’t anticipate the number and variety that I would see. This section of the Bay Trail makes a perimeter loop of Redwood Shores, passing immediately next to, or separated only by sloughs from, Redwood Shores Ecological Reserve, Bair Island Ecological Reserve , and Don Edwards San Francisco Bay National Wildlife Refuge. The route of my hike is described here; this post focuses on the shorebirds and waterfowl.

As far as I know, all of the species I observed are commonly found in the area. However, the close proximity of the walking path to the lagoons, sloughs, and shallow mud flat and salt marsh areas surely contributed to the number and variety of sightings.

The first part of my walk was along the Steinberger Slough on the southeast side of the Redwood Shores peninsula. Just across the slough is shallow salt marsh of Bair Island Ecological Reserve. About 1 mile from my start at the Shore Dogs Park I noticed that I was approaching a section of shoreline where a large crowd of shorebirds was resting, including avocets and at least one other species, difficult to identify since their heads were tucked away. I was a bit surprised that so many individuals were in roosting poses, since it was just about noon on a partly to mostly sunny day.

picture of crowd of shorebirds along Steinberger Slough

Crowd of shorebirds along Steinberger Slough

As I continued toward the closest-approach point, suddenly the entire group took off like a cloud, flew around in big circles for 30-60 seconds, and just as suddenly landed and became quiet again. I suppose something (me?) spooked a few lookouts, and the signal to fly was quickly understood by the entire group.

Nearby there were other individual birds actively feeding. Here is a whimbrel (Numenius phaeopus): note the moderately long down-curved bill and a distinct narrow dark stripe through the eye. I saw a few other long-legged waders later in the walk that I identified mainly by the beak size and shape and sometimes by head plumage or leg color.

image of whimbrel in Steinberger Slough

Whimbrel in Steinberger Slough

A little farther along, I saw a group of canvasbacks (Aythya valisineria), several resting and a couple with their heads up. The one at the upper right provided the best view for identification purposes.

photo of group of canvasbacks

Group of canvasbacks

Closer to shore, in very shallow water, a pair of shovelers (Anas clypeata) was busy shoveling for food. The most distinctive characteristic of shovelers is the large, almost spoon-shaped, beak.

picture of shovelers


After walking along Twin Dolphins Drive I arrived at the southwest end of the long central lagoon of Redwood Shores. Here I found an American egret (Ardea alba), its white plumage in stark contrast to the brilliant green landscaping. Although I’ve posted several pictures of American egrets previously, this time there was a beautifully clear reflection.

image of American egret reflected in the Redwood Shores lagoon

American egret reflected in the Redwood Shores lagoon

There is a smaller lagoon in front of the Oracle corporate campus. In this lagoon I noted a coot and several greater scaups (Aythya marila). The unusual coloring of the water is due to reflection of a brilliant blue sky as well as the buildings and landscaping, in addition to small ripples and the scaup’s wake on the water surface.

photo of greater scaup in the Oracle lagoon

Greater scaup in the Oracle lagoon

After crossing a small pedestrian/bike bridge over Belmont Slough, while making my way toward the Children’s Bridge across US-101, the path goes for a short distance along a narrow canal that connects Belmont and O’Neill Sloughs. At a street underpass, I was startled to see a pair of distinctive hooded mergansers (Lophodytes cucullatus) swimming along. The male is at the right and the female is at the left.

picture of hooded mergansers

Hooded mergansers

Later, while walking along the Belmont Slough, I had a particularly good view of an American avocet (Recurvirostra americana). Note the distinctive plumage as well as the long upturned bill. Avocets are very common and abundant, and I saw them in many locations on this walk, as well as on almost every other shoreline walk I’ve taken in the area.

image of avocet in Belmont Slough

Avocet in Belmont Slough

I saw a few diving birds, but they are sometimes difficult to photograph because they seem to be ready to dive again more quickly than I can get a picture composed. Here is a lucky shot of a Western grebe (Aechmophorus occidentalis) between dives.

photo of Western grebe

Western grebe

And here is a great blue heron (Ardea herodias). Along with the American and snowy egrets, I consider these to be the “big three” shore birds, observed on almost any walk along the Bay shoreline and often along other streams or lakes in the Bay Area. I thought the lighting was especially good for this regal individual.

picture of great blue heron in Belmont Slough

Great blue heron in Belmont Slough

Toward the outer portion of Belmont Slough there is a side trail, about 0.4 mile round trip, to an observation platform overlooking a section of the Redwood Shores Ecological Reserve. I saw several species of shorebirds along this trail, nicely lit in the afternoon sun. One species was the willet (Tringa semipalmata), with a medium-length straight bill and relatively plain buffy plumage.

image of willet


Another was a marbled godwit (Limosa fedoa). Note the much longer bill, with a pink base and dark tip, and more mottled plumage.

photo of marbled godwit

Marbled godwit

Yet another was a long-billed curlew (Numenius americanus). The bill is approximately as long as the marbled godwit’s, but is distinctly down-curved. This one seems to have just captured a snack by burrowing deep into the mud with its long bill.

picture of long-billed curlew with a snack in its beak

Long-billed curlew with a snack in its beak

I also noted a black-necked stilt (Himantopus mexicanus) nicely reflected in some shallow water. The distinctive black and white plumage and long red legs make it easy to identify.

image of black-necked stilt reflected in shallow water in Redwood Shores Ecological Reserve

Black-necked stilt reflected in shallow water in Redwood Shores Ecological Reserve

Out in the more open water of the slough there was a group of buffleheads (Bucephala albeola), here two males and a female. Buffleheads are smaller ducks, and the white head patch on males (along with the small, light blue bill) is distinctive.

photo of buffleheads in Belmont Slough

Buffleheads in Belmont Slough

At the San Francisco Bay end of Belmont Slough the Bay Trail turns right and passes along the Bay Slough. Here I had several more sightings of shorebirds and waterfowl as the time got later in the afternoon: less than 1 hour until sunset. First was a (presumably greater) yellowlegs (Tringa melanoleuca), with a medium-short straight bill and bright yellow legs.

picture of yellowlegs along Bay Slough

Yellowlegs along Bay Slough

There were several pairs of American wigeons (Anas americana), with a distinctive head and body plumage pattern and a small, light-colored bill with a black tip.

image of American wigeon pair in Bay Slough

American wigeon pair in Bay Slough

Last, but not least, I saw several cinnamon teals (Anas cyanoptera). The males are rusty-colored all over, with dark eyes and bill. The blue patch on the wing is often concealed when the wings are folded, but is clear in this picture.

photo of pair of cinnamon teals in Bay Slough

Pair of cinnamon teals in Bay Slough

What a treasure trove of shorebirds and waterfowl! I will look forward to returning to his area, perhaps during a different season, to see what else I can see.

This entry was posted in birding, San Mateo County and tagged , , , , . Bookmark the permalink.

One Response to Birding along the San Francisco Bay Trail at Redwood Shores

  1. Pingback: San Francisco Bay Trail: Redwood Shores | trailhiker

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