When I think of the beach, I can see a line of small grey and white birds scurrying across the sand at the edge of the surf, stopping momentarily to stick their bills into the sand then moving as a wave comes in — Sanderlings. They are poking the sand for their food, small crustaceans and occasionally worms that they pull from the wet sand and insects hopping on the sand.

On Alameda beaches in the winter, they are a study in grey, with a noticeably light grey back, a dark smudge at the front edge of the wing, a pale belly, black legs, and a black bill about as long as their head is wide. In the spring they molt into their summer outfit, with their heads, backs, and throats a mix of cinnamon and dark brown, still with a pale belly. They are bigger and lighter-colored than the other small birds on our shoreline.

On beaches in the winter, they move quickly in small or large groups, following the waves; the size of a group fluctuates constantly as individual birds feed or fly to a new spot. The Sanderling name perfectly describes their feeding style; it comes from an Old English word for someone who “plows the sand.” I’ve watched them run with waves on beaches on the East Coast, in Florida, and along the Pacific Coast, most recently on the beach by the Crab Cove Visitor Center.

A few Sanderlings, usually one-year-old birds, stay here all year but most of the adults leave in May for northern Canada, Greenland, and Siberia, to breed and raise their young. Like many shorebirds, their nests are scrapes in the ground, lined with leaves and grass. The female lays three to four eggs and both parents incubate the eggs for three to four weeks and raise the chicks. Sometimes the female will leave the male to incubate the first batch of eggs and raise those chicks while she lays, incubates and raises a second batch a short distance away.

The down-covered chicks can walk a few hours after they hatch. A day or two after all the eggs hatch, the parents lead all the chicks away from the nest into the surrounding marshland. There the chicks feed on insects on plants and on the water. Parents stay with the chicks as they learn to fly about two-and-a-half weeks after they hatched. Sometimes the female may leave the male to raise his chicks then she finds a second mate and raises a second set of chicks. The adults fly south for the winter while the juvenile birds hang out together for a time before they also head south, guided by their instincts. Sanderlings that winter in California usually return to the same location each winter for their 10 or so adult years.

Changes in their arctic breeding grounds, including drilling for oil, sea level rise, and changes in the time when the insects they eat are hatched because of warmer temperatures combined with greater human use of our beaches, have led to serious drop in the number of Sanderlings in the last 50 years, including fewer Sanderlings on the Pacific Coast. However, you can still find Sanderlings on Crown Memorial Beach, at Elsie Roemer Bird Sanctuary, and at Crab Cove, by looking for small birds moving in and out at the edge of the waves.

Rick Lewis is a volunteer with the Golden Gate Audubon Society.