Knots at the Shell Bar

Sunday March 25, 2018 8:30 AM Foster City Shell Bar

On a Sunday morning as winter slowly slips into spring and the northern migration slowly starts in earnest, I headed to a birding hotspot, just south of the San Mateo Bridge known as Foster City Shell Bar. No this is not birding from the deck of a swanky seafood restaurant but a tidal beach composed of shells and sand.

I parked on Beach Front Boulevard and shouldered my scope and headed up toward the walking and biking path on top of the levy. As I reached the top of the levy and looked down, I was greeted with an eyeful of birds! From the narrow width of the shell beach to the water, the ground was covered with shorebirds.

A carpet of sandpipers.

I walked south, to get better lighting and I set up my scope and aimed it up the beach to see which birds populated the mixed flock. The flock was tightly packed and the most numerus species was the tiny western sandpiper. They were all shoulder to shoulder covering the beach in their carpet of grays, rufous, and black flecks.

I scoped the flock with many species in attendance: western sandpiper, black-bellied plover, dunlin, marbled godwit. Many birds where flying in from the south so I was near impossible to keep an accurate count. Wave after wave of marbled godwits were alighting on the beach.

Among the uniformity of the shorebirds in highest number, I looked for the few individuals that stood out. Like the diminutive semipalmated plover which was taking a bath in the bay. As I scanned to the left the large black and white terns stood out, the otherworldly black skimmer. I had a high count of 17 birds.

At one point, the entire mixed flock burst into the air and flew above the water in the tightly bunched group. After a circuitous journey, the mixed mass alighted back on Shell Beach. Time to rescan the flock.

I picked through the birds that were newly redistributed on the beach and I noticed a large sandpiper that was not a dunlin or dowitcher. This small group was feeding in a distinctive way. It was not playing tag with the tide like a sanderling but it was wading out into the surf, the water up to its belly. This sandpiper was picking food off of the surface and plunging its head into the water. I was looking at one of the most famous long-distant migrants: the red knot! Some red knots migrate 9,000 miles every year, from their breeding grounds in the Arctic to their summer grounds on the southern tip of South America.

Three feeding red knots, note the bird in the back is feeding in the “deeper” end.

Red knots use the San Francisco Bay as a staging area to refuel before they make the journey to their breeding grounds in the Arctic Circle. The birds before me where in their rather drab, winter plumage. A few individuals had a hint of red in their bellies. On their breeding grounds, red knots have a rufous-robin red on their faces, breast, and belly. Soon these bird would be gone and I was enjoying my time with them.

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