These small shorebirds (Calidris alba) are most often seen in groups, chasing the waves in and out looking for food in recently exposed intertidal sand flats. Adults possess a broad white wing stripe bordered in black that is visible in flight. Young birds may appear more mottled, being black and white across their back, streaked with fine black markings. Among other characteristics, the black legs and longer bill clearly distinguish them from piping plovers. But like the piping plover, they spend their winters feeding and roosting along our coastline before they migrate north to the high arctic during the summer breeding season.
Like all shorebirds, they should be watched from a distance and all efforts must be made to avoid disturbing them. The saltmarsh cordgrass (Spartina alterniflora) that washes up on our beaches from the marsh is critically important to all shorebirds. Their long brown stems mass together to form "wrack", usually at the highest reaches of the tides. We leave this wrack in place to give the shorebirds roosting habitat, as it blocks wind and provides a safe area for them to rest and conserve energy between feeding cycles. For some shorebirds it also provides critical nesting habitat as well. The wrack also provides a natural "sand fence" to catch windblown sand and form new sand dunes, which are important to protect our island during storm events.
The Cornell Lab of Ornithology - All About Birds: http://www.allaboutbirds.org/guide/sanderling/id